<?php

/**
 * @file
 * API for the Drupal menu system.
 */

/**
 * @defgroup menu Menu system
 * @{
 * Define the navigation menus, and route page requests to code based on URLs.
 *
 * The Drupal menu system drives both the navigation system from a user
 * perspective and the callback system that Drupal uses to respond to URLs
 * passed from the browser. For this reason, a good understanding of the
 * menu system is fundamental to the creation of complex modules. As a note,
 * this is related to, but separate from menu.module, which allows menus
 * (which in this context are hierarchical lists of links) to be customized from
 * the Drupal administrative interface.
 *
 * Drupal's menu system follows a simple hierarchy defined by paths.
 * Implementations of hook_menu() define menu items and assign them to
 * paths (which should be unique). The menu system aggregates these items
 * and determines the menu hierarchy from the paths. For example, if the
 * paths defined were a, a/b, e, a/b/c/d, f/g, and a/b/h, the menu system
 * would form the structure:
 * - a
 *   - a/b
 *     - a/b/c/d
 *     - a/b/h
 * - e
 * - f/g
 * Note that the number of elements in the path does not necessarily
 * determine the depth of the menu item in the tree.
 *
 * When responding to a page request, the menu system looks to see if the
 * path requested by the browser is registered as a menu item with a
 * callback. If not, the system searches up the menu tree for the most
 * complete match with a callback it can find. If the path a/b/i is
 * requested in the tree above, the callback for a/b would be used.
 *
 * The found callback function is called with any arguments specified
 * in the "page arguments" attribute of its menu item. The
 * attribute must be an array. After these arguments, any remaining
 * components of the path are appended as further arguments. In this
 * way, the callback for a/b above could respond to a request for
 * a/b/i differently than a request for a/b/j.
 *
 * For an illustration of this process, see page_example.module.
 *
 * Access to the callback functions is also protected by the menu system.
 * The "access callback" with an optional "access arguments" of each menu
 * item is called before the page callback proceeds. If this returns TRUE,
 * then access is granted; if FALSE, then access is denied. Default local task
 * menu items (see next paragraph) may omit this attribute to use the value
 * provided by the parent item.
 *
 * In the default Drupal interface, you will notice many links rendered as
 * tabs. These are known in the menu system as "local tasks", and they are
 * rendered as tabs by default, though other presentations are possible.
 * Local tasks function just as other menu items in most respects. It is
 * convention that the names of these tasks should be short verbs if
 * possible. In addition, a "default" local task should be provided for
 * each set. When visiting a local task's parent menu item, the default
 * local task will be rendered as if it is selected; this provides for a
 * normal tab user experience. This default task is special in that it
 * links not to its provided path, but to its parent item's path instead.
 * The default task's path is only used to place it appropriately in the
 * menu hierarchy.
 *
 * Everything described so far is stored in the menu_router table. The
 * menu_links table holds the visible menu links. By default these are
 * derived from the same hook_menu definitions, however you are free to
 * add more with menu_link_save().
 */

/**
 * @defgroup menu_flags Menu flags
 * @{
 * Flags for use in the "type" attribute of menu items.
 */

/**
 * Internal menu flag -- menu item is the root of the menu tree.
 */
define('MENU_IS_ROOT', 0x0001);

/**
 * Internal menu flag -- menu item is visible in the menu tree.
 */
define('MENU_VISIBLE_IN_TREE', 0x0002);

/**
 * Internal menu flag -- menu item is visible in the breadcrumb.
 */
define('MENU_VISIBLE_IN_BREADCRUMB', 0x0004);

/**
 * Internal menu flag -- menu item links back to its parent.
 */
define('MENU_LINKS_TO_PARENT', 0x0008);

/**
 * Internal menu flag -- menu item can be modified by administrator.
 */
define('MENU_MODIFIED_BY_ADMIN', 0x0020);

/**
 * Internal menu flag -- menu item was created by administrator.
 */
define('MENU_CREATED_BY_ADMIN', 0x0040);

/**
 * Internal menu flag -- menu item is a local task.
 */
define('MENU_IS_LOCAL_TASK', 0x0080);

/**
 * Internal menu flag -- menu item is a local action.
 */
define('MENU_IS_LOCAL_ACTION', 0x0100);

/**
 * @} End of "Menu flags".
 */

/**
 * @defgroup menu_item_types Menu item types
 * @{
 * Definitions for various menu item types.
 *
 * Menu item definitions provide one of these constants, which are shortcuts for
 * combinations of @link menu_flags Menu flags @endlink.
 */

/**
 * Menu type -- A "normal" menu item that's shown in menu and breadcrumbs.
 *
 * Normal menu items show up in the menu tree and can be moved/hidden by
 * the administrator. Use this for most menu items. It is the default value if
 * no menu item type is specified.
 */
define('MENU_NORMAL_ITEM', MENU_VISIBLE_IN_TREE | MENU_VISIBLE_IN_BREADCRUMB);

/**
 * Menu type -- A hidden, internal callback, typically used for API calls.
 *
 * Callbacks simply register a path so that the correct function is fired
 * when the URL is accessed. They do not appear in menus or breadcrumbs.
 */
define('MENU_CALLBACK', 0x0000);

/**
 * Menu type -- A normal menu item, hidden until enabled by an administrator.
 *
 * Modules may "suggest" menu items that the administrator may enable. They act
 * just as callbacks do until enabled, at which time they act like normal items.
 * Note for the value: 0x0010 was a flag which is no longer used, but this way
 * the values of MENU_CALLBACK and MENU_SUGGESTED_ITEM are separate.
 */
define('MENU_SUGGESTED_ITEM', MENU_VISIBLE_IN_BREADCRUMB | 0x0010);

/**
 * Menu type -- A task specific to the parent item, usually rendered as a tab.
 *
 * Local tasks are menu items that describe actions to be performed on their
 * parent item. An example is the path "node/52/edit", which performs the
 * "edit" task on "node/52".
 */
define('MENU_LOCAL_TASK', MENU_IS_LOCAL_TASK | MENU_VISIBLE_IN_BREADCRUMB);

/**
 * Menu type -- The "default" local task, which is initially active.
 *
 * Every set of local tasks should provide one "default" task, that links to the
 * same path as its parent when clicked.
 */
define('MENU_DEFAULT_LOCAL_TASK', MENU_IS_LOCAL_TASK | MENU_LINKS_TO_PARENT | MENU_VISIBLE_IN_BREADCRUMB);

/**
 * Menu type -- An action specific to the parent, usually rendered as a link.
 *
 * Local actions are menu items that describe actions on the parent item such
 * as adding a new user, taxonomy term, etc.
 */
define('MENU_LOCAL_ACTION', MENU_IS_LOCAL_TASK | MENU_IS_LOCAL_ACTION | MENU_VISIBLE_IN_BREADCRUMB);

/**
 * @} End of "Menu item types".
 */

/**
 * @defgroup menu_context_types Menu context types
 * @{
 * Flags for use in the "context" attribute of menu router items.
 */

/**
 * Internal menu flag: Invisible local task.
 *
 * This flag may be used for local tasks like "Delete", so custom modules and
 * themes can alter the default context and expose the task by altering menu.
 */
define('MENU_CONTEXT_NONE', 0x0000);

/**
 * Internal menu flag: Local task should be displayed in page context.
 */
define('MENU_CONTEXT_PAGE', 0x0001);

/**
 * Internal menu flag: Local task should be displayed inline.
 */
define('MENU_CONTEXT_INLINE', 0x0002);

/**
 * @} End of "Menu context types".
 */

/**
 * @defgroup menu_status_codes Menu status codes
 * @{
 * Status codes for menu callbacks.
 */

/**
 * Internal menu status code -- Menu item was found.
 */
define('MENU_FOUND', 1);

/**
 * Internal menu status code -- Menu item was not found.
 */
define('MENU_NOT_FOUND', 2);

/**
 * Internal menu status code -- Menu item access is denied.
 */
define('MENU_ACCESS_DENIED', 3);

/**
 * Internal menu status code -- Menu item inaccessible because site is offline.
 */
define('MENU_SITE_OFFLINE', 4);

/**
 * Internal menu status code -- Everything is working fine.
 */
define('MENU_SITE_ONLINE', 5);

/**
 * @} End of "Menu status codes".
 */

/**
 * @defgroup menu_tree_parameters Menu tree parameters
 * @{
 * Parameters for a menu tree.
 */

/**
 * The maximum number of path elements for a menu callback
 */
define('MENU_MAX_PARTS', 9);


/**
 * The maximum depth of a menu links tree - matches the number of p columns.
 */
define('MENU_MAX_DEPTH', 9);


/**
 * @} End of "Menu tree parameters".
 */

/**
 * Reserved key to identify the most specific menu link for a given path.
 *
 * The value of this constant is a hash of the constant name. We use the hash
 * so that the reserved key is over 32 characters in length and will not
 * collide with allowed menu names:
 * @code
 * sha1('MENU_PREFERRED_LINK') = 1cf698d64d1aa4b83907cf6ed55db3a7f8e92c91
 * @endcode
 *
 * @see menu_link_get_preferred()
 */
define('MENU_PREFERRED_LINK', '1cf698d64d1aa4b83907cf6ed55db3a7f8e92c91');

/**
 * Returns the ancestors (and relevant placeholders) for any given path.
 *
 * For example, the ancestors of node/12345/edit are:
 * - node/12345/edit
 * - node/12345/%
 * - node/%/edit
 * - node/%/%
 * - node/12345
 * - node/%
 * - node
 *
 * To generate these, we will use binary numbers. Each bit represents a
 * part of the path. If the bit is 1, then it represents the original
 * value while 0 means wildcard. If the path is node/12/edit/foo
 * then the 1011 bitstring represents node/%/edit/foo where % means that
 * any argument matches that part. We limit ourselves to using binary
 * numbers that correspond the patterns of wildcards of router items that
 * actually exists. This list of 'masks' is built in menu_rebuild().
 *
 * @param $parts
 *   An array of path parts, for the above example
 *   array('node', '12345', 'edit').
 *
 * @return
 *   An array which contains the ancestors and placeholders. Placeholders
 *   simply contain as many '%s' as the ancestors.
 */
function menu_get_ancestors($parts) {
	$number_parts = count($parts);
	$ancestors = array();
	$length =  $number_parts - 1;
	$end = (1 << $number_parts) - 1;
	$masks = variable_get('menu_masks', array());
	// Only examine patterns that actually exist as router items (the masks).
	foreach ($masks as $i) {
		if ($i > $end) {
			// Only look at masks that are not longer than the path of interest.
			continue;
		}
		elseif ($i < (1 << $length)) {
			// We have exhausted the masks of a given length, so decrease the length.
			--$length;
		}
		$current = '';
		for ($j = $length; $j >= 0; $j--) {
			// Check the bit on the $j offset.
			if ($i & (1 << $j)) {
				// Bit one means the original value.
				$current .= $parts[$length - $j];
			}
			else {
				// Bit zero means means wildcard.
				$current .= '%';
			}
			// Unless we are at offset 0, add a slash.
			if ($j) {
				$current .= '/';
			}
		}
		$ancestors[] = $current;
	}
	return $ancestors;
}

/**
 * Unserializes menu data, using a map to replace path elements.
 *
 * The menu system stores various path-related information (such as the 'page
 * arguments' and 'access arguments' components of a menu item) in the database
 * using serialized arrays, where integer values in the arrays represent
 * arguments to be replaced by values from the path. This function first
 * unserializes such menu information arrays, and then does the path
 * replacement.
 *
 * The path replacement acts on each integer-valued element of the unserialized
 * menu data array ($data) using a map array ($map, which is typically an array
 * of path arguments) as a list of replacements. For instance, if there is an
 * element of $data whose value is the number 2, then it is replaced in $data
 * with $map[2]; non-integer values in $data are left alone.
 *
 * As an example, an unserialized $data array with elements ('node_load', 1)
 * represents instructions for calling the node_load() function. Specifically,
 * this instruction says to use the path component at index 1 as the input
 * parameter to node_load(). If the path is 'node/123', then $map will be the
 * array ('node', 123), and the returned array from this function will have
 * elements ('node_load', 123), since $map[1] is 123. This return value will
 * indicate specifically that node_load(123) is to be called to load the node
 * whose ID is 123 for this menu item.
 *
 * @param $data
 *   A serialized array of menu data, as read from the database.
 * @param $map
 *   A path argument array, used to replace integer values in $data; an integer
 *   value N in $data will be replaced by value $map[N]. Typically, the $map
 *   array is generated from a call to the arg() function.
 *
 * @return
 *   The unserialized $data array, with path arguments replaced.
 */
function menu_unserialize($data, $map) {
	if ($data = unserialize($data)) {
		foreach ($data as $k => $v) {
			if (is_int($v)) {
				$data[$k] = isset($map[$v]) ? $map[$v] : '';
			}
		}
		return $data;
	}
	else {
		return array();
	}
}



/**
 * Replaces the statically cached item for a given path.
 *
 * @param $path
 *   The path.
 * @param $router_item
 *   The router item. Usually you take a router entry from menu_get_item and
 *   set it back either modified or to a different path. This lets you modify the
 *   navigation block, the page title, the breadcrumb and the page help in one
 *   call.
 */
function menu_set_item($path, $router_item) {
	menu_get_item($path, $router_item);
}

/**
 * Get a router item.
 *
 * @param $path
 *   The path, for example node/5. The function will find the corresponding
 *   node/% item and return that.
 * @param $router_item
 *   Internal use only.
 *
 * @return
 *   The router item, an associate array corresponding to one row in the
 *   menu_router table. The value of key map holds the loaded objects. The
 *   value of key access is TRUE if the current user can access this page.
 *   The values for key title, page_arguments, access_arguments, and
 *   theme_arguments will be filled in based on the database values and the
 *   objects loaded.
 */
function menu_get_item($path = NULL, $router_item = NULL) {
	$router_items = &drupal_static(__FUNCTION__);
	if (!isset($path)) {
		$path = $_GET['q'];
	}
	if (isset($router_item)) {
		$router_items[$path] = $router_item;
	}
	if (!isset($router_items[$path])) {
		// Rebuild if we know it's needed, or if the menu masks are missing which
		// occurs rarely, likely due to a race condition of multiple rebuilds.
		if (variable_get('menu_rebuild_needed', FALSE) || !variable_get('menu_masks', array())) {
			menu_rebuild();
		}
		$original_map = arg(NULL, $path);

		// Since there is no limit to the length of $path, use a hash to keep it
		// short yet unique.
		$cid = 'menu_item:' . hash('sha256', $path);
		if ($cached = cache_get($cid, 'cache_menu')) {
			$router_item = $cached->data;
		}
		else {
			$parts = array_slice($original_map, 0, MENU_MAX_PARTS);
			$ancestors = menu_get_ancestors($parts);
			$router_item = db_query_range('SELECT * FROM {menu_router} WHERE path IN (:ancestors) ORDER BY fit DESC', 0, 1, array(':ancestors' => $ancestors))->fetchAssoc();
			cache_set($cid, $router_item, 'cache_menu');
		}
		if ($router_item) {
			// Allow modules to alter the router item before it is translated and
			// checked for access.
			drupal_alter('menu_get_item', $router_item, $path, $original_map);

			$map = _menu_translate($router_item, $original_map);
			$router_item['original_map'] = $original_map;
			if ($map === FALSE) {
				$router_items[$path] = FALSE;
				return FALSE;
			}
			if ($router_item['access']) {
				$router_item['map'] = $map;
				$router_item['page_arguments'] = array_merge(menu_unserialize($router_item['page_arguments'], $map), array_slice($map, $router_item['number_parts']));
				$router_item['theme_arguments'] = array_merge(menu_unserialize($router_item['theme_arguments'], $map), array_slice($map, $router_item['number_parts']));
			}
		}
		$router_items[$path] = $router_item;
	}
	return $router_items[$path];
}

/**
 * Execute the page callback associated with the current path.
 *
 * @param $path
 *   The drupal path whose handler is to be be executed. If set to NULL, then
 *   the current path is used.
 * @param $deliver
 *   (optional) A boolean to indicate whether the content should be sent to the
 *   browser using the appropriate delivery callback (TRUE) or whether to return
 *   the result to the caller (FALSE).
 */
function menu_execute_active_handler($path = NULL, $deliver = TRUE) {
	// Check if site is offline.
	$page_callback_result = _menu_site_is_offline() ? MENU_SITE_OFFLINE : MENU_SITE_ONLINE;

	// Allow other modules to change the site status but not the path because that
	// would not change the global variable. hook_url_inbound_alter() can be used
	// to change the path. Code later will not use the $read_only_path variable.
	$read_only_path = !empty($path) ? $path : $_GET['q'];
	drupal_alter('menu_site_status', $page_callback_result, $read_only_path);

	// Only continue if the site status is not set.
	if ($page_callback_result == MENU_SITE_ONLINE) {
		if ($router_item = menu_get_item($path)) {
			if ($router_item['access']) {
				if ($router_item['include_file']) {
					require_once DRUPAL_ROOT . '/' . $router_item['include_file'];
				}
				$page_callback_result = call_user_func_array($router_item['page_callback'], $router_item['page_arguments']);
			}
			else {
				$page_callback_result = MENU_ACCESS_DENIED;
			}
		}
		else {
			$page_callback_result = MENU_NOT_FOUND;
		}
	}

	// Deliver the result of the page callback to the browser, or if requested,
	// return it raw, so calling code can do more processing.
	if ($deliver) {
		$default_delivery_callback = (isset($router_item) && $router_item) ? $router_item['delivery_callback'] : NULL;
		drupal_deliver_page($page_callback_result, $default_delivery_callback);
	}
	else {
		return $page_callback_result;
	}
}

/**
 * Loads objects into the map as defined in the $item['load_functions'].
 *
 * @param $item
 *   A menu router or menu link item
 * @param $map
 *   An array of path arguments (ex: array('node', '5'))
 *
 * @return
 *   Returns TRUE for success, FALSE if an object cannot be loaded.
 *   Names of object loading functions are placed in $item['load_functions'].
 *   Loaded objects are placed in $map[]; keys are the same as keys in the
 *   $item['load_functions'] array.
 *   $item['access'] is set to FALSE if an object cannot be loaded.
 */
function _menu_load_objects(&$item, &$map) {
	if ($load_functions = $item['load_functions']) {
		// If someone calls this function twice, then unserialize will fail.
		if (!is_array($load_functions)) {
			$load_functions = unserialize($load_functions);
		}
		$path_map = $map;
		foreach ($load_functions as $index => $function) {
			if ($function) {
				$value = isset($path_map[$index]) ? $path_map[$index] : '';
				if (is_array($function)) {
					// Set up arguments for the load function. These were pulled from
					// 'load arguments' in the hook_menu() entry, but they need
					// some processing. In this case the $function is the key to the
					// load_function array, and the value is the list of arguments.
					list($function, $args) = each($function);
					$load_functions[$index] = $function;

					// Some arguments are placeholders for dynamic items to process.
					foreach ($args as $i => $arg) {
						if ($arg === '%index') {
							// Pass on argument index to the load function, so multiple
							// occurrences of the same placeholder can be identified.
							$args[$i] = $index;
						}
						if ($arg === '%map') {
							// Pass on menu map by reference. The accepting function must
							// also declare this as a reference if it wants to modify
							// the map.
							$args[$i] = &$map;
						}
						if (is_int($arg)) {
							$args[$i] = isset($path_map[$arg]) ? $path_map[$arg] : '';
						}
					}
					array_unshift($args, $value);
					$return = call_user_func_array($function, $args);
				}
				else {
					$return = $function($value);
				}
				// If callback returned an error or there is no callback, trigger 404.
				if ($return === FALSE) {
					$item['access'] = FALSE;
					$map = FALSE;
					return FALSE;
				}
				$map[$index] = $return;
			}
		}
		$item['load_functions'] = $load_functions;
	}
	return TRUE;
}

/**
 * Check access to a menu item using the access callback
 *
 * @param $item
 *   A menu router or menu link item
 * @param $map
 *   An array of path arguments (ex: array('node', '5'))
 *
 * @return
 *   $item['access'] becomes TRUE if the item is accessible, FALSE otherwise.
 */
function _menu_check_access(&$item, $map) {
	// Determine access callback, which will decide whether or not the current
	// user has access to this path.
	$callback = empty($item['access_callback']) ? 0 : trim($item['access_callback']);
	// Check for a TRUE or FALSE value.
	if (is_numeric($callback)) {
		$item['access'] = (bool) $callback;
	}
	else {
		$arguments = menu_unserialize($item['access_arguments'], $map);
		// As call_user_func_array is quite slow and user_access is a very common
		// callback, it is worth making a special case for it.
		if ($callback == 'user_access') {
			$item['access'] = (count($arguments) == 1) ? user_access($arguments[0]) : user_access($arguments[0], $arguments[1]);
		}
		elseif (function_exists($callback)) {
			$item['access'] = call_user_func_array($callback, $arguments);
		}
	}
}

/**
 * Localize the router item title using t() or another callback.
 *
 * Translate the title and description to allow storage of English title
 * strings in the database, yet display of them in the language required
 * by the current user.
 *
 * @param $item
 *   A menu router item or a menu link item.
 * @param $map
 *   The path as an array with objects already replaced. E.g., for path
 *   node/123 $map would be array('node', $node) where $node is the node
 *   object for node 123.
 * @param $link_translate
 *   TRUE if we are translating a menu link item; FALSE if we are
 *   translating a menu router item.
 *
 * @return
 *   No return value.
 *   $item['title'] is localized according to $item['title_callback'].
 *   If an item's callback is check_plain(), $item['options']['html'] becomes
 *   TRUE.
 *   $item['description'] is translated using t().
 *   When doing link translation and the $item['options']['attributes']['title']
 *   (link title attribute) matches the description, it is translated as well.
 */
function _menu_item_localize(&$item, $map, $link_translate = FALSE) {
	$callback = $item['title_callback'];
	$item['localized_options'] = $item['options'];
	// All 'class' attributes are assumed to be an array during rendering, but
	// links stored in the database may use an old string value.
	// @todo In order to remove this code we need to implement a database update
	//   including unserializing all existing link options and running this code
	//   on them, as well as adding validation to menu_link_save().
	if (isset($item['options']['attributes']['class']) && is_string($item['options']['attributes']['class'])) {
		$item['localized_options']['attributes']['class'] = explode(' ', $item['options']['attributes']['class']);
	}
	// If we are translating the title of a menu link, and its title is the same
	// as the corresponding router item, then we can use the title information
	// from the router. If it's customized, then we need to use the link title
	// itself; can't localize.
	// If we are translating a router item (tabs, page, breadcrumb), then we
	// can always use the information from the router item.
	if (!$link_translate || ($item['title'] == $item['link_title'])) {
		// t() is a special case. Since it is used very close to all the time,
		// we handle it directly instead of using indirect, slower methods.
		if ($callback == 't') {
			if (empty($item['title_arguments'])) {
				$item['title'] = t($item['title']);
			}
			else {
				$item['title'] = t($item['title'], menu_unserialize($item['title_arguments'], $map));
			}
		}
		elseif ($callback && function_exists($callback)) {
			if (empty($item['title_arguments'])) {
				$item['title'] = $callback($item['title']);
			}
			else {
				$item['title'] = call_user_func_array($callback, menu_unserialize($item['title_arguments'], $map));
			}
			// Avoid calling check_plain again on l() function.
			if ($callback == 'check_plain') {
				$item['localized_options']['html'] = TRUE;
			}
		}
	}
	elseif ($link_translate) {
		$item['title'] = $item['link_title'];
	}

	// Translate description, see the motivation above.
	if (!empty($item['description'])) {
		$original_description = $item['description'];
		$item['description'] = t($item['description']);
		if ($link_translate && isset($item['options']['attributes']['title']) && $item['options']['attributes']['title'] == $original_description) {
			$item['localized_options']['attributes']['title'] = $item['description'];
		}
	}
}

/**
 * Handles dynamic path translation and menu access control.
 *
 * When a user arrives on a page such as node/5, this function determines
 * what "5" corresponds to, by inspecting the page's menu path definition,
 * node/%node. This will call node_load(5) to load the corresponding node
 * object.
 *
 * It also works in reverse, to allow the display of tabs and menu items which
 * contain these dynamic arguments, translating node/%node to node/5.
 *
 * Translation of menu item titles and descriptions are done here to
 * allow for storage of English strings in the database, and translation
 * to the language required to generate the current page.
 *
 * @param $router_item
 *   A menu router item
 * @param $map
 *   An array of path arguments (ex: array('node', '5'))
 * @param $to_arg
 *   Execute $item['to_arg_functions'] or not. Use only if you want to render a
 *   path from the menu table, for example tabs.
 *
 * @return
 *   Returns the map with objects loaded as defined in the
 *   $item['load_functions']. $item['access'] becomes TRUE if the item is
 *   accessible, FALSE otherwise. $item['href'] is set according to the map.
 *   If an error occurs during calling the load_functions (like trying to load
 *   a non existing node) then this function return FALSE.
 */
function _menu_translate(&$router_item, $map, $to_arg = FALSE) {
	if ($to_arg && !empty($router_item['to_arg_functions'])) {
		// Fill in missing path elements, such as the current uid.
		_menu_link_map_translate($map, $router_item['to_arg_functions']);
	}
	// The $path_map saves the pieces of the path as strings, while elements in
	// $map may be replaced with loaded objects.
	$path_map = $map;
	if (!empty($router_item['load_functions']) && !_menu_load_objects($router_item, $map)) {
		// An error occurred loading an object.
		$router_item['access'] = FALSE;
		return FALSE;
	}

	// Generate the link path for the page request or local tasks.
	$link_map = explode('/', $router_item['path']);
	if (isset($router_item['tab_root'])) {
		$tab_root_map = explode('/', $router_item['tab_root']);
	}
	if (isset($router_item['tab_parent'])) {
		$tab_parent_map = explode('/', $router_item['tab_parent']);
	}
	for ($i = 0; $i < $router_item['number_parts']; $i++) {
		if ($link_map[$i] == '%') {
			$link_map[$i] = $path_map[$i];
		}
		if (isset($tab_root_map[$i]) && $tab_root_map[$i] == '%') {
			$tab_root_map[$i] = $path_map[$i];
		}
		if (isset($tab_parent_map[$i]) && $tab_parent_map[$i] == '%') {
			$tab_parent_map[$i] = $path_map[$i];
		}
	}
	$router_item['href'] = implode('/', $link_map);
	$router_item['tab_root_href'] = implode('/', $tab_root_map);
	$router_item['tab_parent_href'] = implode('/', $tab_parent_map);
	$router_item['options'] = array();
	_menu_check_access($router_item, $map);

	// For performance, don't localize an item the user can't access.
	if ($router_item['access']) {
		_menu_item_localize($router_item, $map);
	}

	return $map;
}

/**
 * This function translates the path elements in the map using any to_arg
 * helper function. These functions take an argument and return an object.
 * See http://drupal.org/node/109153 for more information.
 *
 * @param $map
 *   An array of path arguments (ex: array('node', '5'))
 * @param $to_arg_functions
 *   An array of helper function (ex: array(2 => 'menu_tail_to_arg'))
 */
function _menu_link_map_translate(&$map, $to_arg_functions) {
	$to_arg_functions = unserialize($to_arg_functions);
	foreach ($to_arg_functions as $index => $function) {
		// Translate place-holders into real values.
		$arg = $function(!empty($map[$index]) ? $map[$index] : '', $map, $index);
		if (!empty($map[$index]) || isset($arg)) {
			$map[$index] = $arg;
		}
		else {
			unset($map[$index]);
		}
	}
}

/**
 * Returns path as one string from the argument we are currently at.
 */
function menu_tail_to_arg($arg, $map, $index) {
	return implode('/', array_slice($map, $index));
}

/**
 * Loads path as one string from the argument we are currently at.
 *
 * To use this load function, you must specify the load arguments
 * in the router item as:
 * @code
 * $item['load arguments'] = array('%map', '%index');
 * @endcode
 *
 * @see search_menu().
 */
function menu_tail_load($arg, &$map, $index) {
	$arg = implode('/', array_slice($map, $index));
	$map = array_slice($map, 0, $index);
	return $arg;
}

/**
 * This function is similar to _menu_translate() but does link-specific
 * preparation such as always calling to_arg functions
 *
 * @param $item
 *   A menu link.
 * @param $translate
 *   (optional) Whether to try to translate a link containing dynamic path
 *   argument placeholders (%) based on the menu router item of the current
 *   path. Defaults to FALSE. Internally used for breadcrumbs.
 *
 * @return
 *   Returns the map of path arguments with objects loaded as defined in the
 *   $item['load_functions'].
 *   $item['access'] becomes TRUE if the item is accessible, FALSE otherwise.
 *   $item['href'] is generated from link_path, possibly by to_arg functions.
 *   $item['title'] is generated from link_title, and may be localized.
 *   $item['options'] is unserialized; it is also changed within the call here
 *   to $item['localized_options'] by _menu_item_localize().
 */
function _menu_link_translate(&$item, $translate = FALSE) {
	if (!is_array($item['options'])) {
		$item['options'] = unserialize($item['options']);
	}
	if ($item['external']) {
		$item['access'] = 1;
		$map = array();
		$item['href'] = $item['link_path'];
		$item['title'] = $item['link_title'];
		$item['localized_options'] = $item['options'];
	}
	else {
		// Complete the path of the menu link with elements from the current path,
		// if it contains dynamic placeholders (%).
		$map = explode('/', $item['link_path']);
		if (strpos($item['link_path'], '%') !== FALSE) {
			// Invoke registered to_arg callbacks.
			if (!empty($item['to_arg_functions'])) {
				_menu_link_map_translate($map, $item['to_arg_functions']);
			}
			// Or try to derive the path argument map from the current router item,
			// if this $item's path is within the router item's path. This means
			// that if we are on the current path 'foo/%/bar/%/baz', then
			// menu_get_item() will have translated the menu router item for the
			// current path, and we can take over the argument map for a link like
			// 'foo/%/bar'. This inheritance is only valid for breadcrumb links.
			// @see _menu_tree_check_access()
			// @see menu_get_active_breadcrumb()
			elseif ($translate && ($current_router_item = menu_get_item())) {
				// If $translate is TRUE, then this link is in the active trail.
				// Only translate paths within the current path.
				if (strpos($current_router_item['path'], $item['link_path']) === 0) {
					$count = count($map);
					$map = array_slice($current_router_item['original_map'], 0, $count);
					$item['original_map'] = $map;
					if (isset($current_router_item['map'])) {
						$item['map'] = array_slice($current_router_item['map'], 0, $count);
					}
					// Reset access to check it (for the first time).
					unset($item['access']);
				}
			}
		}
		$item['href'] = implode('/', $map);

		// Skip links containing untranslated arguments.
		if (strpos($item['href'], '%') !== FALSE) {
			$item['access'] = FALSE;
			return FALSE;
		}
		// menu_tree_check_access() may set this ahead of time for links to nodes.
		if (!isset($item['access'])) {
			if (!empty($item['load_functions']) && !_menu_load_objects($item, $map)) {
				// An error occurred loading an object.
				$item['access'] = FALSE;
				return FALSE;
			}
			_menu_check_access($item, $map);
		}
		// For performance, don't localize a link the user can't access.
		if ($item['access']) {
			_menu_item_localize($item, $map, TRUE);
		}
	}

	// Allow other customizations - e.g. adding a page-specific query string to the
	// options array. For performance reasons we only invoke this hook if the link
	// has the 'alter' flag set in the options array.
	if (!empty($item['options']['alter'])) {
		drupal_alter('translated_menu_link', $item, $map);
	}

	return $map;
}

/**
 * Get a loaded object from a router item.
 *
 * menu_get_object() provides access to objects loaded by the current router
 * item. For example, on the page node/%node, the router loads the %node object,
 * and calling menu_get_object() will return that. Normally, it is necessary to
 * specify the type of object referenced, however node is the default.
 * The following example tests to see whether the node being displayed is of the
 * "story" content type:
 * @code
 * $node = menu_get_object();
 * $story = $node->type == 'story';
 * @endcode
 *
 * @param $type
 *   Type of the object. These appear in hook_menu definitions as %type. Core
 *   provides aggregator_feed, aggregator_category, contact, filter_format,
 *   forum_term, menu, menu_link, node, taxonomy_vocabulary, user. See the
 *   relevant {$type}_load function for more on each. Defaults to node.
 * @param $position
 *   The position of the object in the path, where the first path segment is 0.
 *   For node/%node, the position of %node is 1, but for comment/reply/%node,
 *   it's 2. Defaults to 1.
 * @param $path
 *   See menu_get_item() for more on this. Defaults to the current path.
 */
function menu_get_object($type = 'node', $position = 1, $path = NULL) {
	$router_item = menu_get_item($path);
	if (isset($router_item['load_functions'][$position]) && !empty($router_item['map'][$position]) && $router_item['load_functions'][$position] == $type . '_load') {
		return $router_item['map'][$position];
	}
}

/**
 * Renders a menu tree based on the current path.
 *
 * The tree is expanded based on the current path and dynamic paths are also
 * changed according to the defined to_arg functions (for example the 'My
 * account' link is changed from user/% to a link with the current user's uid).
 *
 * @param $menu_name
 *   The name of the menu.
 *
 * @return
 *   A structured array representing the specified menu on the current page, to
 *   be rendered by drupal_render().
 */
function menu_tree($menu_name) {
	$menu_output = &drupal_static(__FUNCTION__, array());

	if (!isset($menu_output[$menu_name])) {
		$tree = menu_tree_page_data($menu_name);
		$menu_output[$menu_name] = menu_tree_output($tree);
	}
	return $menu_output[$menu_name];
}

/**
 * Returns a rendered menu tree.
 *
 * The menu item's LI element is given one of the following classes:
 * - expanded: The menu item is showing its submenu.
 * - collapsed: The menu item has a submenu which is not shown.
 * - leaf: The menu item has no submenu.
 *
 * @param $tree
 *   A data structure representing the tree as returned from menu_tree_data.
 *
 * @return
 *   A structured array to be rendered by drupal_render().
 */
function menu_tree_output($tree) {
	$build = array();
	$items = array();

	// Pull out just the menu links we are going to render so that we
	// get an accurate count for the first/last classes.
	foreach ($tree as $data) {
		if ($data['link']['access'] && !$data['link']['hidden']) {
			$items[] = $data;
		}
	}

	$router_item = menu_get_item();
	$num_items = count($items);
	foreach ($items as $i => $data) {
		$class = array();
		if ($i == 0) {
			$class[] = 'first';
		}
		if ($i == $num_items - 1) {
			$class[] = 'last';
		}
		// Set a class for the <li>-tag. Since $data['below'] may contain local
		// tasks, only set 'expanded' class if the link also has children within
		// the current menu.
		if ($data['link']['has_children'] && $data['below']) {
			$class[] = 'expanded';
		}
		elseif ($data['link']['has_children']) {
			$class[] = 'collapsed';
		}
		else {
			$class[] = 'leaf';
		}
		// Set a class if the link is in the active trail.
		if ($data['link']['in_active_trail']) {
			$class[] = 'active-trail';
			$data['link']['localized_options']['attributes']['class'][] = 'active-trail';
		}
		// Normally, l() compares the href of every link with $_GET['q'] and sets
		// the active class accordingly. But local tasks do not appear in menu
		// trees, so if the current path is a local task, and this link is its
		// tab root, then we have to set the class manually.
		if ($data['link']['href'] == $router_item['tab_root_href'] && $data['link']['href'] != $_GET['q']) {
			$data['link']['localized_options']['attributes']['class'][] = 'active';
		}

		// Allow menu-specific theme overrides.
		$element['#theme'] = 'menu_link__' . strtr($data['link']['menu_name'], '-', '_');
		$element['#attributes']['class'] = $class;
		$element['#title'] = $data['link']['title'];
		$element['#href'] = $data['link']['href'];
		$element['#localized_options'] = !empty($data['link']['localized_options']) ? $data['link']['localized_options'] : array();
		$element['#below'] = $data['below'] ? menu_tree_output($data['below']) : $data['below'];
		$element['#original_link'] = $data['link'];
		// Index using the link's unique mlid.
		$build[$data['link']['mlid']] = $element;
	}
	if ($build) {
		// Make sure drupal_render() does not re-order the links.
		$build['#sorted'] = TRUE;
		// Add the theme wrapper for outer markup.
		// Allow menu-specific theme overrides.
		$build['#theme_wrappers'][] = 'menu_tree__' . strtr($data['link']['menu_name'], '-', '_');
	}

	return $build;
}

/**
 * Get the data structure representing a named menu tree.
 *
 * Since this can be the full tree including hidden items, the data returned
 * may be used for generating an an admin interface or a select.
 *
 * @param $menu_name
 *   The named menu links to return
 * @param $link
 *   A fully loaded menu link, or NULL. If a link is supplied, only the
 *   path to root will be included in the returned tree - as if this link
 *   represented the current page in a visible menu.
 * @param $max_depth
 *   Optional maximum depth of links to retrieve. Typically useful if only one
 *   or two levels of a sub tree are needed in conjunction with a non-NULL
 *   $link, in which case $max_depth should be greater than $link['depth'].
 *
 * @return
 *   An tree of menu links in an array, in the order they should be rendered.
 */
function menu_tree_all_data($menu_name, $link = NULL, $max_depth = NULL) {
	$tree = &drupal_static(__FUNCTION__, array());

	// Use $mlid as a flag for whether the data being loaded is for the whole tree.
	$mlid = isset($link['mlid']) ? $link['mlid'] : 0;
	// Generate a cache ID (cid) specific for this $menu_name, $link, $language, and depth.
	$cid = 'links:' . $menu_name . ':all:' . $mlid . ':' . $GLOBALS['language']->language . ':' . (int) $max_depth;

	if (!isset($tree[$cid])) {
		// If the static variable doesn't have the data, check {cache_menu}.
		$cache = cache_get($cid, 'cache_menu');
		if ($cache && isset($cache->data)) {
			// If the cache entry exists, it contains the parameters for
			// menu_build_tree().
			$tree_parameters = $cache->data;
		}
		// If the tree data was not in the cache, build $tree_parameters.
		if (!isset($tree_parameters)) {
			$tree_parameters = array(
					'min_depth' => 1,
					'max_depth' => $max_depth,
			);
			if ($mlid) {
				// The tree is for a single item, so we need to match the values in its
				// p columns and 0 (the top level) with the plid values of other links.
				$parents = array(0);
				for ($i = 1; $i < MENU_MAX_DEPTH; $i++) {
					if (!empty($link["p$i"])) {
						$parents[] = $link["p$i"];
					}
				}
				$tree_parameters['expanded'] = $parents;
				$tree_parameters['active_trail'] = $parents;
				$tree_parameters['active_trail'][] = $mlid;
			}

			// Cache the tree building parameters using the page-specific cid.
			cache_set($cid, $tree_parameters, 'cache_menu');
		}

		// Build the tree using the parameters; the resulting tree will be cached
		// by _menu_build_tree()).
		$tree[$cid] = menu_build_tree($menu_name, $tree_parameters);
	}

	return $tree[$cid];
}

/**
 * Set the path for determining the active trail of the specified menu tree.
 *
 * This path will also affect the breadcrumbs under some circumstances.
 * Breadcrumbs are built using the preferred link returned by
 * menu_link_get_preferred(). If the preferred link is inside one of the menus
 * specified in calls to menu_tree_set_path(), the preferred link will be
 * overridden by the corresponding path returned by menu_tree_get_path().
 *
 * Setting this path does not affect the main content; for that use
 * menu_set_active_item() instead.
 *
 * @param $menu_name
 *   The name of the affected menu tree.
 * @param $path
 *   The path to use when finding the active trail.
 */
function menu_tree_set_path($menu_name, $path = NULL) {
	$paths = &drupal_static(__FUNCTION__);
	if (isset($path)) {
		$paths[$menu_name] = $path;
	}
	return isset($paths[$menu_name]) ? $paths[$menu_name] : NULL;
}

/**
 * Get the path for determining the active trail of the specified menu tree.
 *
 * @param $menu_name
 *   The menu name of the requested tree.
 *
 * @return
 *   A string containing the path. If no path has been specified with
 *   menu_tree_set_path(), NULL is returned.
 */
function menu_tree_get_path($menu_name) {
	return menu_tree_set_path($menu_name);
}

/**
 * Get the data structure representing a named menu tree, based on the current page.
 *
 * The tree order is maintained by storing each parent in an individual
 * field, see http://drupal.org/node/141866 for more.
 *
 * @param $menu_name
 *   The named menu links to return.
 * @param $max_depth
 *   (optional) The maximum depth of links to retrieve.
 * @param $only_active_trail
 *   (optional) Whether to only return the links in the active trail (TRUE)
 *   instead of all links on every level of the menu link tree (FALSE). Defaults
 *   to FALSE. Internally used for breadcrumbs only.
 *
 * @return
 *   An array of menu links, in the order they should be rendered. The array
 *   is a list of associative arrays -- these have two keys, link and below.
 *   link is a menu item, ready for theming as a link. Below represents the
 *   submenu below the link if there is one, and it is a subtree that has the
 *   same structure described for the top-level array.
 */
function menu_tree_page_data($menu_name, $max_depth = NULL, $only_active_trail = FALSE) {
	$tree = &drupal_static(__FUNCTION__, array());

	// Check if the active trail has been overridden for this menu tree.
	$active_path = menu_tree_get_path($menu_name);
	// Load the menu item corresponding to the current page.
	if ($item = menu_get_item($active_path)) {
		if (isset($max_depth)) {
			$max_depth = min($max_depth, MENU_MAX_DEPTH);
		}
		// Generate a cache ID (cid) specific for this page.
		$cid = 'links:' . $menu_name . ':page:' . $item['href'] . ':' . $GLOBALS['language']->language . ':' . (int) $item['access'] . ':' . (int) $max_depth;
		// If we are asked for the active trail only, and $menu_name has not been
		// built and cached for this page yet, then this likely means that it
		// won't be built anymore, as this function is invoked from
		// template_process_page(). So in order to not build a giant menu tree
		// that needs to be checked for access on all levels, we simply check
		// whether we have the menu already in cache, or otherwise, build a minimum
		// tree containing the breadcrumb/active trail only.
		// @see menu_set_active_trail()
		if (!isset($tree[$cid]) && $only_active_trail) {
			$cid .= ':trail';
		}

		if (!isset($tree[$cid])) {
			// If the static variable doesn't have the data, check {cache_menu}.
			$cache = cache_get($cid, 'cache_menu');
			if ($cache && isset($cache->data)) {
				// If the cache entry exists, it contains the parameters for
				// menu_build_tree().
				$tree_parameters = $cache->data;
			}
			// If the tree data was not in the cache, build $tree_parameters.
			if (!isset($tree_parameters)) {
				$tree_parameters = array(
						'min_depth' => 1,
						'max_depth' => $max_depth,
				);
				// Parent mlids; used both as key and value to ensure uniqueness.
				// We always want all the top-level links with plid == 0.
				$active_trail = array(0 => 0);

				// If the item for the current page is accessible, build the tree
				// parameters accordingly.
				if ($item['access']) {
					// Find a menu link corresponding to the current path. If $active_path
					// is NULL, let menu_link_get_preferred() determine the path.
					if ($active_link = menu_link_get_preferred($active_path, $menu_name)) {
						// The active link may only be taken into account to build the
						// active trail, if it resides in the requested menu. Otherwise,
						// we'd needlessly re-run _menu_build_tree() queries for every menu
						// on every page.
						if ($active_link['menu_name'] == $menu_name) {
							// Use all the coordinates, except the last one because there
							// can be no child beyond the last column.
							for ($i = 1; $i < MENU_MAX_DEPTH; $i++) {
								if ($active_link['p' . $i]) {
									$active_trail[$active_link['p' . $i]] = $active_link['p' . $i];
								}
							}
							// If we are asked to build links for the active trail only, skip
							// the entire 'expanded' handling.
							if ($only_active_trail) {
								$tree_parameters['only_active_trail'] = TRUE;
							}
						}
					}
					$parents = $active_trail;

					$expanded = variable_get('menu_expanded', array());
					// Check whether the current menu has any links set to be expanded.
					if (!$only_active_trail && in_array($menu_name, $expanded)) {
						// Collect all the links set to be expanded, and then add all of
						// their children to the list as well.
						do {
							$result = db_select('menu_links', NULL, array('fetch' => PDO::FETCH_ASSOC))
							->fields('menu_links', array('mlid'))
							->condition('menu_name', $menu_name)
							->condition('expanded', 1)
							->condition('has_children', 1)
							->condition('plid', $parents, 'IN')
							->condition('mlid', $parents, 'NOT IN')
							->execute();
							$num_rows = FALSE;
							foreach ($result as $item) {
								$parents[$item['mlid']] = $item['mlid'];
								$num_rows = TRUE;
							}
						} while ($num_rows);
					}
					$tree_parameters['expanded'] = $parents;
					$tree_parameters['active_trail'] = $active_trail;
				}
				// If access is denied, we only show top-level links in menus.
				else {
					$tree_parameters['expanded'] = $active_trail;
					$tree_parameters['active_trail'] = $active_trail;
				}
				// Cache the tree building parameters using the page-specific cid.
				cache_set($cid, $tree_parameters, 'cache_menu');
			}

			// Build the tree using the parameters; the resulting tree will be cached
			// by _menu_build_tree().
			$tree[$cid] = menu_build_tree($menu_name, $tree_parameters);
		}
		return $tree[$cid];
	}

	return array();
}

/**
 * Build a menu tree, translate links, and check access.
 *
 * @param $menu_name
 *   The name of the menu.
 * @param $parameters
 *   (optional) An associative array of build parameters. Possible keys:
 *   - expanded: An array of parent link ids to return only menu links that are
 *     children of one of the plids in this list. If empty, the whole menu tree
 *     is built, unless 'only_active_trail' is TRUE.
 *   - active_trail: An array of mlids, representing the coordinates of the
 *     currently active menu link.
 *   - only_active_trail: Whether to only return links that are in the active
 *     trail. This option is ignored, if 'expanded' is non-empty. Internally
 *     used for breadcrumbs.
 *   - min_depth: The minimum depth of menu links in the resulting tree.
 *     Defaults to 1, which is the default to build a whole tree for a menu, i.e.
 *     excluding menu container itself.
 *   - max_depth: The maximum depth of menu links in the resulting tree.
 *   - conditions: An associative array of custom database select query
 *     condition key/value pairs; see _menu_build_tree() for the actual query.
 *
 * @return
 *   A fully built menu tree.
 */
function menu_build_tree($menu_name, array $parameters = array()) {
	// Build the menu tree.
	$data = _menu_build_tree($menu_name, $parameters);
	// Check access for the current user to each item in the tree.
	menu_tree_check_access($data['tree'], $data['node_links']);
	return $data['tree'];
}

/**
 * Build a menu tree.
 *
 * This function may be used build the data for a menu tree only, for example
 * to further massage the data manually before further processing happens.
 * menu_tree_check_access() needs to be invoked afterwards.
 *
 * @see menu_build_tree()
 */
function _menu_build_tree($menu_name, array $parameters = array()) {
	// Static cache of already built menu trees.
	$trees = &drupal_static(__FUNCTION__, array());

	// Build the cache id; sort parents to prevent duplicate storage and remove
	// default parameter values.
	if (isset($parameters['expanded'])) {
		sort($parameters['expanded']);
	}
	$tree_cid = 'links:' . $menu_name . ':tree-data:' . $GLOBALS['language']->language . ':' . hash('sha256', serialize($parameters));

	// If we do not have this tree in the static cache, check {cache_menu}.
	if (!isset($trees[$tree_cid])) {
		$cache = cache_get($tree_cid, 'cache_menu');
		if ($cache && isset($cache->data)) {
			$trees[$tree_cid] = $cache->data;
		}
	}

	if (!isset($trees[$tree_cid])) {
		// Select the links from the table, and recursively build the tree. We
		// LEFT JOIN since there is no match in {menu_router} for an external
		// link.
		$query = db_select('menu_links', 'ml', array('fetch' => PDO::FETCH_ASSOC));
		$query->addTag('translatable');
		$query->leftJoin('menu_router', 'm', 'm.path = ml.router_path');
		$query->fields('ml');
		$query->fields('m', array(
				'load_functions',
				'to_arg_functions',
				'access_callback',
				'access_arguments',
				'page_callback',
				'page_arguments',
				'delivery_callback',
				'tab_parent',
				'tab_root',
				'title',
				'title_callback',
				'title_arguments',
				'theme_callback',
				'theme_arguments',
				'type',
				'description',
		));
		for ($i = 1; $i <= MENU_MAX_DEPTH; $i++) {
			$query->orderBy('p' . $i, 'ASC');
		}
		$query->condition('ml.menu_name', $menu_name);
		if (!empty($parameters['expanded'])) {
			$query->condition('ml.plid', $parameters['expanded'], 'IN');
		}
		elseif (!empty($parameters['only_active_trail'])) {
			$query->condition('ml.mlid', $parameters['active_trail'], 'IN');
		}
		$min_depth = (isset($parameters['min_depth']) ? $parameters['min_depth'] : 1);
		if ($min_depth != 1) {
			$query->condition('ml.depth', $min_depth, '>=');
		}
		if (isset($parameters['max_depth'])) {
			$query->condition('ml.depth', $parameters['max_depth'], '<=');
		}
		// Add custom query conditions, if any were passed.
		if (isset($parameters['conditions'])) {
			foreach ($parameters['conditions'] as $column => $value) {
				$query->condition($column, $value);
			}
		}

		// Build an ordered array of links using the query result object.
		$links = array();
		foreach ($query->execute() as $item) {
			$links[] = $item;
		}
		$active_trail = (isset($parameters['active_trail']) ? $parameters['active_trail'] : array());
		$data['tree'] = menu_tree_data($links, $active_trail, $min_depth);
		$data['node_links'] = array();
		menu_tree_collect_node_links($data['tree'], $data['node_links']);

		// Cache the data, if it is not already in the cache.
		cache_set($tree_cid, $data, 'cache_menu');
		$trees[$tree_cid] = $data;
	}

	return $trees[$tree_cid];
}

/**
 * Recursive helper function - collect node links.
 *
 * @param $tree
 *   The menu tree you wish to collect node links from.
 * @param $node_links
 *   An array in which to store the collected node links.
 */
function menu_tree_collect_node_links(&$tree, &$node_links) {
	foreach ($tree as $key => $v) {
		if ($tree[$key]['link']['router_path'] == 'node/%') {
			$nid = substr($tree[$key]['link']['link_path'], 5);
			if (is_numeric($nid)) {
				$node_links[$nid][$tree[$key]['link']['mlid']] = &$tree[$key]['link'];
				$tree[$key]['link']['access'] = FALSE;
			}
		}
		if ($tree[$key]['below']) {
			menu_tree_collect_node_links($tree[$key]['below'], $node_links);
		}
	}
}

/**
 * Check access and perform other dynamic operations for each link in the tree.
 *
 * @param $tree
 *   The menu tree you wish to operate on.
 * @param $node_links
 *   A collection of node link references generated from $tree by
 *   menu_tree_collect_node_links().
 */
function menu_tree_check_access(&$tree, $node_links = array()) {
	if ($node_links) {
		$nids = array_keys($node_links);
		$select = db_select('node', 'n');
		$select->addField('n', 'nid');
		$select->condition('n.status', 1);
		$select->condition('n.nid', $nids, 'IN');
		$select->addTag('node_access');
		$nids = $select->execute()->fetchCol();
		foreach ($nids as $nid) {
			foreach ($node_links[$nid] as $mlid => $link) {
				$node_links[$nid][$mlid]['access'] = TRUE;
			}
		}
	}
	_menu_tree_check_access($tree);
}

/**
 * Recursive helper function for menu_tree_check_access()
 */
function _menu_tree_check_access(&$tree) {
	$new_tree = array();
	foreach ($tree as $key => $v) {
		$item = &$tree[$key]['link'];
		_menu_link_translate($item);
		if ($item['access'] || ($item['in_active_trail'] && strpos($item['href'], '%') !== FALSE)) {
			if ($tree[$key]['below']) {
				_menu_tree_check_access($tree[$key]['below']);
			}
			// The weights are made a uniform 5 digits by adding 50000 as an offset.
			// After _menu_link_translate(), $item['title'] has the localized link title.
			// Adding the mlid to the end of the index insures that it is unique.
			$new_tree[(50000 + $item['weight']) . ' ' . $item['title'] . ' ' . $item['mlid']] = $tree[$key];
		}
	}
	// Sort siblings in the tree based on the weights and localized titles.
	ksort($new_tree);
	$tree = $new_tree;
}

/**
 * Builds the data representing a menu tree.
 *
 * @param $links
 *   A flat array of menu links that are part of the menu. Each array element
 *   is an associative array of information about the menu link, containing the
 *   fields from the {menu_links} table, and optionally additional information
 *   from the {menu_router} table, if the menu item appears in both tables.
 *   This array must be ordered depth-first. See _menu_build_tree() for a sample
 *   query.
 * @param $parents
 *   An array of the menu link ID values that are in the path from the current
 *   page to the root of the menu tree.
 * @param $depth
 *   The minimum depth to include in the returned menu tree.
 *
 * @return
 *   An array of menu links in the form of a tree. Each item in the tree is an
 *   associative array containing:
 *   - link: The menu link item from $links, with additional element
 *     'in_active_trail' (TRUE if the link ID was in $parents).
 *   - below: An array containing the sub-tree of this item, where each element
 *     is a tree item array with 'link' and 'below' elements. This array will be
 *     empty if the menu item has no items in its sub-tree having a depth
 *     greater than or equal to $depth.
 */
function menu_tree_data(array $links, array $parents = array(), $depth = 1) {
	// Reverse the array so we can use the more efficient array_pop() function.
	$links = array_reverse($links);
	return _menu_tree_data($links, $parents, $depth);
}

/**
 * Recursive helper function to build the data representing a menu tree.
 *
 * The function is a bit complex because the rendering of a link depends on
 * the next menu link.
 */
function _menu_tree_data(&$links, $parents, $depth) {
	$tree = array();
	while ($item = array_pop($links)) {
		// We need to determine if we're on the path to root so we can later build
		// the correct active trail and breadcrumb.
		$item['in_active_trail'] = in_array($item['mlid'], $parents);
		// Add the current link to the tree.
		$tree[$item['mlid']] = array(
				'link' => $item,
				'below' => array(),
		);
		// Look ahead to the next link, but leave it on the array so it's available
		// to other recursive function calls if we return or build a sub-tree.
		$next = end($links);
		// Check whether the next link is the first in a new sub-tree.
		if ($next && $next['depth'] > $depth) {
			// Recursively call _menu_tree_data to build the sub-tree.
			$tree[$item['mlid']]['below'] = _menu_tree_data($links, $parents, $next['depth']);
			// Fetch next link after filling the sub-tree.
			$next = end($links);
		}
		// Determine if we should exit the loop and return.
		if (!$next || $next['depth'] < $depth) {
			break;
		}
	}
	return $tree;
}

/**
 * Preprocesses the rendered tree for theme_menu_tree().
 */
function template_preprocess_menu_tree(&$variables) {
	$variables['tree'] = $variables['tree']['#children'];
}

/**
 * Returns HTML for a wrapper for a menu sub-tree.
 *
 * @param $variables
 *   An associative array containing:
 *   - tree: An HTML string containing the tree's items.
 *
 * @see template_preprocess_menu_tree()
 * @ingroup themeable
 */
function theme_menu_tree($variables) {
	return '<ul class="menu">' . $variables['tree'] . '</ul>';
}

/**
 * Returns HTML for a menu link and submenu.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: Structured array data for a menu link.
 *
 * @ingroup themeable
 */
function theme_menu_link(array $variables) {
	$element = $variables['element'];
	$sub_menu = '';

	if ($element['#below']) {
		$sub_menu = drupal_render($element['#below']);
	}
	$output = l($element['#title'], $element['#href'], $element['#localized_options']);
	return '<li' . drupal_attributes($element['#attributes']) . '>' . $output . $sub_menu . "</li>\n";
}

/**
 * Returns HTML for a single local task link.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: A render element containing:
 *     - #link: A menu link array with 'title', 'href', and 'localized_options'
 *       keys.
 *     - #active: A boolean indicating whether the local task is active.
 *
 * @ingroup themeable
 */
function theme_menu_local_task($variables) {
	$link = $variables['element']['#link'];
	$link_text = $link['title'];

	if (!empty($variables['element']['#active'])) {
		// Add text to indicate active tab for non-visual users.
		$active = '<span class="element-invisible">' . t('(active tab)') . '</span>';

		// If the link does not contain HTML already, check_plain() it now.
		// After we set 'html'=TRUE the link will not be sanitized by l().
		if (empty($link['localized_options']['html'])) {
			$link['title'] = check_plain($link['title']);
		}
		$link['localized_options']['html'] = TRUE;
		$link_text = t('!local-task-title!active', array('!local-task-title' => $link['title'], '!active' => $active));
	}

	return '<li' . (!empty($variables['element']['#active']) ? ' class="active"' : '') . '>' . l($link_text, $link['href'], $link['localized_options']) . "</li>\n";
}

/**
 * Returns HTML for a single local action link.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: A render element containing:
 *     - #link: A menu link array with 'title', 'href', and 'localized_options'
 *       keys.
 *
 * @ingroup themeable
 */
function theme_menu_local_action($variables) {
	$link = $variables['element']['#link'];

	$output = '<li>';
	if (isset($link['href'])) {
		$output .= l($link['title'], $link['href'], isset($link['localized_options']) ? $link['localized_options'] : array());
	}
	elseif (!empty($link['localized_options']['html'])) {
		$output .= $link['title'];
	}
	else {
		$output .= check_plain($link['title']);
	}
	$output .= "</li>\n";

	return $output;
}

/**
 * Generates elements for the $arg array in the help hook.
 */
function drupal_help_arg($arg = array()) {
	// Note - the number of empty elements should be > MENU_MAX_PARTS.
	return $arg + array('', '', '', '', '', '', '', '', '', '', '', '');
}

/**
 * Returns the help associated with the active menu item.
 */
function menu_get_active_help() {
	$output = '';
	$router_path = menu_tab_root_path();
	// We will always have a path unless we are on a 403 or 404.
	if (!$router_path) {
		return '';
	}

	$arg = drupal_help_arg(arg(NULL));

	foreach (module_implements('help') as $module) {
		$function = $module . '_help';
		// Lookup help for this path.
		if ($help = $function($router_path, $arg)) {
			$output .= $help . "\n";
		}
	}
	return $output;
}

/**
 * Gets the custom theme for the current page, if there is one.
 *
 * @param $initialize
 *   This parameter should only be used internally; it is set to TRUE in order
 *   to force the custom theme to be initialized for the current page request.
 *
 * @return
 *   The machine-readable name of the custom theme, if there is one.
 *
 * @see menu_set_custom_theme()
 */
function menu_get_custom_theme($initialize = FALSE) {
	$custom_theme = &drupal_static(__FUNCTION__);
	// Skip this if the site is offline or being installed or updated, since the
	// menu system may not be correctly initialized then.
	if ($initialize && !_menu_site_is_offline(TRUE) && (!defined('MAINTENANCE_MODE') || (MAINTENANCE_MODE != 'update' && MAINTENANCE_MODE != 'install'))) {
		// First allow modules to dynamically set a custom theme for the current
		// page. Since we can only have one, the last module to return a valid
		// theme takes precedence.
		$custom_themes = array_filter(module_invoke_all('custom_theme'), 'drupal_theme_access');
		if (!empty($custom_themes)) {
			$custom_theme = array_pop($custom_themes);
		}
		// If there is a theme callback function for the current page, execute it.
		// If this returns a valid theme, it will override any theme that was set
		// by a hook_custom_theme() implementation above.
		$router_item = menu_get_item();
		if (!empty($router_item['access']) && !empty($router_item['theme_callback']) && function_exists($router_item['theme_callback'])) {
			$theme_name = call_user_func_array($router_item['theme_callback'], $router_item['theme_arguments']);
			if (drupal_theme_access($theme_name)) {
				$custom_theme = $theme_name;
			}
		}
	}
	return $custom_theme;
}

/**
 * Sets a custom theme for the current page, if there is one.
 */
function menu_set_custom_theme() {
	menu_get_custom_theme(TRUE);
}

/**
 * Build a list of named menus.
 */
function menu_get_names() {
	$names = &drupal_static(__FUNCTION__);

	if (empty($names)) {
		$names = db_select('menu_links')
		->distinct()
		->fields('menu_links', array('menu_name'))
		->orderBy('menu_name')
		->execute()->fetchCol();
	}
	return $names;
}

/**
 * Return an array containing the names of system-defined (default) menus.
 */
function menu_list_system_menus() {
	return array(
			'navigation' => 'Navigation',
			'management' => 'Management',
			'user-menu' => 'User menu',
			'main-menu' => 'Main menu',
	);
}

/**
 * Return an array of links to be rendered as the Main menu.
 */
function menu_main_menu() {
	return menu_navigation_links(variable_get('menu_main_links_source', 'main-menu'));
}

/**
 * Return an array of links to be rendered as the Secondary links.
 */
function menu_secondary_menu() {

	// If the secondary menu source is set as the primary menu, we display the
	// second level of the primary menu.
	if (variable_get('menu_secondary_links_source', 'user-menu') == variable_get('menu_main_links_source', 'main-menu')) {
		return menu_navigation_links(variable_get('menu_main_links_source', 'main-menu'), 1);
	}
	else {
		return menu_navigation_links(variable_get('menu_secondary_links_source', 'user-menu'), 0);
	}
}

/**
 * Return an array of links for a navigation menu.
 *
 * @param $menu_name
 *   The name of the menu.
 * @param $level
 *   Optional, the depth of the menu to be returned.
 *
 * @return
 *   An array of links of the specified menu and level.
 */
function menu_navigation_links($menu_name, $level = 0) {
	// Don't even bother querying the menu table if no menu is specified.
	if (empty($menu_name)) {
		return array();
	}

	// Get the menu hierarchy for the current page.
	$tree = menu_tree_page_data($menu_name, $level + 1);

	// Go down the active trail until the right level is reached.
	while ($level-- > 0 && $tree) {
		// Loop through the current level's items until we find one that is in trail.
		while ($item = array_shift($tree)) {
			if ($item['link']['in_active_trail']) {
				// If the item is in the active trail, we continue in the subtree.
				$tree = empty($item['below']) ? array() : $item['below'];
				break;
			}
		}
	}

	// Create a single level of links.
	$router_item = menu_get_item();
	$links = array();
	foreach ($tree as $item) {
		if (!$item['link']['hidden']) {
			$class = '';
			$l = $item['link']['localized_options'];
			$l['href'] = $item['link']['href'];
			$l['title'] = $item['link']['title'];
			if ($item['link']['in_active_trail']) {
				$class = ' active-trail';
				$l['attributes']['class'][] = 'active-trail';
			}
			// Normally, l() compares the href of every link with $_GET['q'] and sets
			// the active class accordingly. But local tasks do not appear in menu
			// trees, so if the current path is a local task, and this link is its
			// tab root, then we have to set the class manually.
			if ($item['link']['href'] == $router_item['tab_root_href'] && $item['link']['href'] != $_GET['q']) {
				$l['attributes']['class'][] = 'active';
			}
			// Keyed with the unique mlid to generate classes in theme_links().
			$links['menu-' . $item['link']['mlid'] . $class] = $l;
		}
	}
	return $links;
}

/**
 * Collects the local tasks (tabs), action links, and the root path.
 *
 * @param $level
 *   The level of tasks you ask for. Primary tasks are 0, secondary are 1.
 *
 * @return
 *   An array containing
 *   - tabs: Local tasks for the requested level:
 *     - count: The number of local tasks.
 *     - output: The themed output of local tasks.
 *   - actions: Action links for the requested level:
 *     - count: The number of action links.
 *     - output: The themed output of action links.
 *   - root_path: The router path for the current page. If the current page is
 *     a default local task, then this corresponds to the parent tab.
 */
function menu_local_tasks($level = 0) {
	$data = &drupal_static(__FUNCTION__);
	$root_path = &drupal_static(__FUNCTION__ . ':root_path', '');
	$empty = array(
			'tabs' => array('count' => 0, 'output' => array()),
			'actions' => array('count' => 0, 'output' => array()),
			'root_path' => &$root_path,
	);

	if (!isset($data)) {
		$data = array();
		// Set defaults in case there are no actions or tabs.
		$actions = $empty['actions'];
		$tabs = array();

		$router_item = menu_get_item();

		// If this router item points to its parent, start from the parents to
		// compute tabs and actions.
		if ($router_item && ($router_item['type'] & MENU_LINKS_TO_PARENT)) {
			$router_item = menu_get_item($router_item['tab_parent_href']);
		}

		// If we failed to fetch a router item or the current user doesn't have
		// access to it, don't bother computing the tabs.
		if (!$router_item || !$router_item['access']) {
			return $empty;
		}

		// Get all tabs (also known as local tasks) and the root page.
		$result = db_select('menu_router', NULL, array('fetch' => PDO::FETCH_ASSOC))
		->fields('menu_router')
		->condition('tab_root', $router_item['tab_root'])
		->condition('context', MENU_CONTEXT_INLINE, '<>')
		->orderBy('weight')
		->orderBy('title')
		->execute();
		$map = $router_item['original_map'];
		$children = array();
		$tasks = array();
		$root_path = $router_item['path'];

		foreach ($result as $item) {
			_menu_translate($item, $map, TRUE);
			if ($item['tab_parent']) {
				// All tabs, but not the root page.
				$children[$item['tab_parent']][$item['path']] = $item;
			}
			// Store the translated item for later use.
			$tasks[$item['path']] = $item;
		}

		// Find all tabs below the current path.
		$path = $router_item['path'];
		// Tab parenting may skip levels, so the number of parts in the path may not
		// equal the depth. Thus we use the $depth counter (offset by 1000 for ksort).
		$depth = 1001;
		$actions['count'] = 0;
		$actions['output'] = array();
		while (isset($children[$path])) {
			$tabs_current = array();
			$actions_current = array();
			$next_path = '';
			$tab_count = 0;
			$action_count = 0;
			foreach ($children[$path] as $item) {
				// Local tasks can be normal items too, so bitmask with
				// MENU_IS_LOCAL_TASK before checking.
				if (!($item['type'] & MENU_IS_LOCAL_TASK)) {
					// This item is not a tab, skip it.
					continue;
				}
				if ($item['access']) {
					$link = $item;
					// The default task is always active. As tabs can be normal items
					// too, so bitmask with MENU_LINKS_TO_PARENT before checking.
					if (($item['type'] & MENU_LINKS_TO_PARENT) == MENU_LINKS_TO_PARENT) {
						// Find the first parent which is not a default local task or action.
						for ($p = $item['tab_parent']; ($tasks[$p]['type'] & MENU_LINKS_TO_PARENT) == MENU_LINKS_TO_PARENT; $p = $tasks[$p]['tab_parent']);
						// Use the path of the parent instead.
						$link['href'] = $tasks[$p]['href'];
						// Mark the link as active, if the current path happens to be the
						// path of the default local task itself (i.e., instead of its
						// tab_parent_href or tab_root_href). Normally, links for default
						// local tasks link to their parent, but the path of default local
						// tasks can still be accessed directly, in which case this link
						// would not be marked as active, since l() only compares the href
						// with $_GET['q'].
						if ($link['href'] != $_GET['q']) {
							$link['localized_options']['attributes']['class'][] = 'active';
						}
						$tabs_current[] = array(
								'#theme' => 'menu_local_task',
								'#link' => $link,
								'#active' => TRUE,
						);
						$next_path = $item['path'];
						$tab_count++;
					}
					else {
						// Actions can be normal items too, so bitmask with
						// MENU_IS_LOCAL_ACTION before checking.
						if (($item['type'] & MENU_IS_LOCAL_ACTION) == MENU_IS_LOCAL_ACTION) {
							// The item is an action, display it as such.
							$actions_current[] = array(
									'#theme' => 'menu_local_action',
									'#link' => $link,
							);
							$action_count++;
						}
						else {
							// Otherwise, it's a normal tab.
							$tabs_current[] = array(
									'#theme' => 'menu_local_task',
									'#link' => $link,
							);
							$tab_count++;
						}
					}
				}
			}
			$path = $next_path;
			$tabs[$depth]['count'] = $tab_count;
			$tabs[$depth]['output'] = $tabs_current;
			$actions['count'] += $action_count;
			$actions['output'] = array_merge($actions['output'], $actions_current);
			$depth++;
		}
		$data['actions'] = $actions;
		// Find all tabs at the same level or above the current one.
		$parent = $router_item['tab_parent'];
		$path = $router_item['path'];
		$current = $router_item;
		$depth = 1000;
		while (isset($children[$parent])) {
			$tabs_current = array();
			$next_path = '';
			$next_parent = '';
			$count = 0;
			foreach ($children[$parent] as $item) {
				// Skip local actions.
				if ($item['type'] & MENU_IS_LOCAL_ACTION) {
					continue;
				}
				if ($item['access']) {
					$count++;
					$link = $item;
					// Local tasks can be normal items too, so bitmask with
					// MENU_LINKS_TO_PARENT before checking.
					if (($item['type'] & MENU_LINKS_TO_PARENT) == MENU_LINKS_TO_PARENT) {
						// Find the first parent which is not a default local task.
						for ($p = $item['tab_parent']; ($tasks[$p]['type'] & MENU_LINKS_TO_PARENT) == MENU_LINKS_TO_PARENT; $p = $tasks[$p]['tab_parent']);
						// Use the path of the parent instead.
						$link['href'] = $tasks[$p]['href'];
						if ($item['path'] == $router_item['path']) {
							$root_path = $tasks[$p]['path'];
						}
					}
					// We check for the active tab.
					if ($item['path'] == $path) {
						// Mark the link as active, if the current path is a (second-level)
						// local task of a default local task. Since this default local task
						// links to its parent, l() will not mark it as active, as it only
						// compares the link's href to $_GET['q'].
						if ($link['href'] != $_GET['q']) {
							$link['localized_options']['attributes']['class'][] = 'active';
						}
						$tabs_current[] = array(
								'#theme' => 'menu_local_task',
								'#link' => $link,
								'#active' => TRUE,
						);
						$next_path = $item['tab_parent'];
						if (isset($tasks[$next_path])) {
							$next_parent = $tasks[$next_path]['tab_parent'];
						}
					}
					else {
						$tabs_current[] = array(
								'#theme' => 'menu_local_task',
								'#link' => $link,
						);
					}
				}
			}
			$path = $next_path;
			$parent = $next_parent;
			$tabs[$depth]['count'] = $count;
			$tabs[$depth]['output'] = $tabs_current;
			$depth--;
		}
		// Sort by depth.
		ksort($tabs);
		// Remove the depth, we are interested only in their relative placement.
		$tabs = array_values($tabs);
		$data['tabs'] = $tabs;

		// Allow modules to alter local tasks or dynamically append further tasks.
		drupal_alter('menu_local_tasks', $data, $router_item, $root_path);
	}

	if (isset($data['tabs'][$level])) {
		return array(
				'tabs' => $data['tabs'][$level],
				'actions' => $data['actions'],
				'root_path' => $root_path,
		);
	}
	// @todo If there are no tabs, then there still can be actions; for example,
	//   when added via hook_menu_local_tasks_alter().
	elseif (!empty($data['actions']['output'])) {
		return array('actions' => $data['actions']) + $empty;
	}
	return $empty;
}

/**
 * Retrieve contextual links for a system object based on registered local tasks.
 *
 * This leverages the menu system to retrieve the first layer of registered
 * local tasks for a given system path. All local tasks of the tab type
 * MENU_CONTEXT_INLINE are taken into account.
 *
 * @see hook_menu()
 *
 * For example, when considering the following registered local tasks:
 * - node/%node/view (default local task) with no 'context' defined
 * - node/%node/edit with context: MENU_CONTEXT_PAGE | MENU_CONTEXT_INLINE
 * - node/%node/revisions with context: MENU_CONTEXT_PAGE
 * - node/%node/report-as-spam with context: MENU_CONTEXT_INLINE
 *
 * If the path "node/123" is passed to this function, then it will return the
 * links for 'edit' and 'report-as-spam'.
 *
 * @param $module
 *   The name of the implementing module. This is used to prefix the key for
 *   each contextual link, which is transformed into a CSS class during
 *   rendering by theme_links(). For example, if $module is 'block' and the
 *   retrieved local task path argument is 'edit', then the resulting CSS class
 *   will be 'block-edit'.
 * @param $parent_path
 *   The static menu router path of the object to retrieve local tasks for, for
 *   example 'node' or 'admin/structure/block/manage'.
 * @param $args
 *   A list of dynamic path arguments to append to $parent_path to form the
 *   fully-qualified menu router path, for example array(123) for a certain
 *   node or array('system', 'navigation') for a certain block.
 *
 * @return
 *   A list of menu router items that are local tasks for the passed-in path.
 *
 * @see contextual_links_preprocess()
 */
function menu_contextual_links($module, $parent_path, $args) {
	static $path_empty = array();

	$links = array();
	// Performance: In case a previous invocation for the same parent path did not
	// return any links, we immediately return here.
	if (isset($path_empty[$parent_path])) {
		return $links;
	}
	// Construct the item-specific parent path.
	$path = $parent_path . '/' . implode('/', $args);

	// Get the router item for the given parent link path.
	$router_item = menu_get_item($path);
	if (!$router_item || !$router_item['access']) {
		$path_empty[$parent_path] = TRUE;
		return $links;
	}
	$data = &drupal_static(__FUNCTION__, array());
	$root_path = $router_item['path'];

	// Performance: For a single, normalized path (such as 'node/%') we only query
	// available tasks once per request.
	if (!isset($data[$root_path])) {
		// Get all contextual links that are direct children of the router item and
		// not of the tab type 'view'.
		$data[$root_path] = db_select('menu_router', 'm')
		->fields('m')
		->condition('tab_parent', $router_item['tab_root'])
		->condition('context', MENU_CONTEXT_NONE, '<>')
		->condition('context', MENU_CONTEXT_PAGE, '<>')
		->orderBy('weight')
		->orderBy('title')
		->execute()
		->fetchAllAssoc('path', PDO::FETCH_ASSOC);
	}
	$parent_length = drupal_strlen($root_path) + 1;
	$map = $router_item['original_map'];
	foreach ($data[$root_path] as $item) {
		// Extract the actual "task" string from the path argument.
		$key = drupal_substr($item['path'], $parent_length);

		// Denormalize and translate the contextual link.
		_menu_translate($item, $map, TRUE);
		if (!$item['access']) {
			continue;
		}
		// All contextual links are keyed by the actual "task" path argument,
		// prefixed with the name of the implementing module.
		$links[$module . '-' . $key] = $item;
	}

	// Allow modules to alter contextual links.
	drupal_alter('menu_contextual_links', $links, $router_item, $root_path);

	// Performance: If the current user does not have access to any links for this
	// router path and no other module added further links, we assign FALSE here
	// to skip the entire process the next time the same router path is requested.
	if (empty($links)) {
		$path_empty[$parent_path] = TRUE;
	}

	return $links;
}

/**
 * Returns the rendered local tasks at the top level.
 */
function menu_primary_local_tasks() {
	$links = menu_local_tasks(0);
	// Do not display single tabs.
	return ($links['tabs']['count'] > 1 ? $links['tabs']['output'] : '');
}

/**
 * Returns the rendered local tasks at the second level.
 */
function menu_secondary_local_tasks() {
	$links = menu_local_tasks(1);
	// Do not display single tabs.
	return ($links['tabs']['count'] > 1 ? $links['tabs']['output'] : '');
}

/**
 * Returns the rendered local actions at the current level.
 */
function menu_local_actions() {
	$links = menu_local_tasks();
	return $links['actions']['output'];
}

/**
 * Returns the router path, or the path of the parent tab of a default local task.
 */
function menu_tab_root_path() {
	$links = menu_local_tasks();
	return $links['root_path'];
}

/**
 * Returns a renderable element for the primary and secondary tabs.
 */
function menu_local_tabs() {
	return array(
			'#theme' => 'menu_local_tasks',
			'#primary' => menu_primary_local_tasks(),
			'#secondary' => menu_secondary_local_tasks(),
	);
}

/**
 * Returns HTML for primary and secondary local tasks.
 *
 * @ingroup themeable
 */
function theme_menu_local_tasks(&$variables) {
	$output = '';

	if (!empty($variables['primary'])) {
		$variables['primary']['#prefix'] = '<h2 class="element-invisible">' . t('Primary tabs') . '</h2>';
		$variables['primary']['#prefix'] .= '<ul class="tabs primary">';
		$variables['primary']['#suffix'] = '</ul>';
		$output .= drupal_render($variables['primary']);
	}
	if (!empty($variables['secondary'])) {
		$variables['secondary']['#prefix'] = '<h2 class="element-invisible">' . t('Secondary tabs') . '</h2>';
		$variables['secondary']['#prefix'] .= '<ul class="tabs secondary">';
		$variables['secondary']['#suffix'] = '</ul>';
		$output .= drupal_render($variables['secondary']);
	}

	return $output;
}

/**
 * Set (or get) the active menu for the current page - determines the active trail.
 *
 * @return
 *   An array of menu machine names, in order of preference. The
 *   'menu_default_active_menus' variable may be used to assert a menu order
 *   different from the order of creation, or to prevent a particular menu from
 *   being used at all in the active trail.
 *   E.g., $conf['menu_default_active_menus'] = array('navigation', 'main-menu')
 */
function menu_set_active_menu_names($menu_names = NULL) {
	$active = &drupal_static(__FUNCTION__);

	if (isset($menu_names) && is_array($menu_names)) {
		$active = $menu_names;
	}
	elseif (!isset($active)) {
		$active = variable_get('menu_default_active_menus', array_keys(menu_list_system_menus()));
	}
	return $active;
}

/**
 * Get the active menu for the current page - determines the active trail.
 */
function menu_get_active_menu_names() {
	return menu_set_active_menu_names();
}

/**
 * Set the active path, which determines which page is loaded.
 *
 * Note that this may not have the desired effect unless invoked very early
 * in the page load, such as during hook_boot, or unless you call
 * menu_execute_active_handler() to generate your page output.
 *
 * @param $path
 *   A Drupal path - not a path alias.
 */
function menu_set_active_item($path) {
	$_GET['q'] = $path;
}

/**
 * Sets the active trail (path to menu tree root) of the current page.
 *
 * Any trail set by this function will only be used for functionality that calls
 * menu_get_active_trail(). Drupal core only uses trails set here for
 * breadcrumbs and the page title and not for menu trees or page content.
 * Additionally, breadcrumbs set by drupal_set_breadcrumb() will override any
 * trail set here.
 *
 * To affect the trail used by menu trees, use menu_tree_set_path(). To affect
 * the page content, use menu_set_active_item() instead.
 *
 * @param $new_trail
 *   Menu trail to set; the value is saved in a static variable and can be
 *   retrieved by menu_get_active_trail(). The format of this array should be
 *   the same as the return value of menu_get_active_trail().
 *
 * @return
 *   The active trail. See menu_get_active_trail() for details.
 */
function menu_set_active_trail($new_trail = NULL) {
	$trail = &drupal_static(__FUNCTION__);

	if (isset($new_trail)) {
		$trail = $new_trail;
	}
	elseif (!isset($trail)) {
		$trail = array();
		$trail[] = array(
				'title' => t('Home'),
				'href' => '<front>',
				'link_path' => '',
				'localized_options' => array(),
				'type' => 0,
		);

		// Try to retrieve a menu link corresponding to the current path. If more
		// than one exists, the link from the most preferred menu is returned.
		$preferred_link = menu_link_get_preferred();
		$current_item = menu_get_item();

		// There is a link for the current path.
		if ($preferred_link) {
			// Pass TRUE for $only_active_trail to make menu_tree_page_data() build
			// a stripped down menu tree containing the active trail only, in case
			// the given menu has not been built in this request yet.
			$tree = menu_tree_page_data($preferred_link['menu_name'], NULL, TRUE);
			list($key, $curr) = each($tree);
		}
		// There is no link for the current path.
		else {
			$preferred_link = $current_item;
			$curr = FALSE;
		}

		while ($curr) {
			$link = $curr['link'];
			if ($link['in_active_trail']) {
				// Add the link to the trail, unless it links to its parent.
				if (!($link['type'] & MENU_LINKS_TO_PARENT)) {
					// The menu tree for the active trail may contain additional links
					// that have not been translated yet, since they contain dynamic
					// argument placeholders (%). Such links are not contained in regular
					// menu trees, and have only been loaded for the additional
					// translation that happens here, so as to be able to display them in
					// the breadcumb for the current page.
					// @see _menu_tree_check_access()
					// @see _menu_link_translate()
					if (strpos($link['href'], '%') !== FALSE) {
						_menu_link_translate($link, TRUE);
					}
					if ($link['access']) {
						$trail[] = $link;
					}
				}
				$tree = $curr['below'] ? $curr['below'] : array();
			}
			list($key, $curr) = each($tree);
		}
		// Make sure the current page is in the trail to build the page title, by
		// appending either the preferred link or the menu router item for the
		// current page. Exclude it if we are on the front page.
		$last = end($trail);
		if ($last['href'] != $preferred_link['href'] && !drupal_is_front_page()) {
			$trail[] = $preferred_link;
		}
	}
	return $trail;
}

/**
 * Lookup the preferred menu link for a given system path.
 *
 * @param $path
 *   The path, for example 'node/5'. The function will find the corresponding
 *   menu link ('node/5' if it exists, or fallback to 'node/%').
 * @param $selected_menu
 *   The name of a menu used to restrict the search for a preferred menu link.
 *   If not specified, all the menus returned by menu_get_active_menu_names()
 *   will be used.
 *
 * @return
 *   A fully translated menu link, or FALSE if no matching menu link was
 *   found. The most specific menu link ('node/5' preferred over 'node/%') in
 *   the most preferred menu (as defined by menu_get_active_menu_names()) is
 *   returned.
 */
function menu_link_get_preferred($path = NULL, $selected_menu = NULL) {
	$preferred_links = &drupal_static(__FUNCTION__);

	if (!isset($path)) {
		$path = $_GET['q'];
	}

	if (empty($selected_menu)) {
		// Use an illegal menu name as the key for the preferred menu link.
		$selected_menu = MENU_PREFERRED_LINK;
	}

	if (!isset($preferred_links[$path])) {
		// Look for the correct menu link by building a list of candidate paths,
		// which are ordered by priority (translated hrefs are preferred over
		// untranslated paths). Afterwards, the most relevant path is picked from
		// the menus, ordered by menu preference.
		$item = menu_get_item($path);
		$path_candidates = array();
		// 1. The current item href.
		$path_candidates[$item['href']] = $item['href'];
		// 2. The tab root href of the current item (if any).
		if ($item['tab_parent'] && ($tab_root = menu_get_item($item['tab_root_href']))) {
			$path_candidates[$tab_root['href']] = $tab_root['href'];
		}
		// 3. The current item path (with wildcards).
		$path_candidates[$item['path']] = $item['path'];
		// 4. The tab root path of the current item (if any).
		if (!empty($tab_root)) {
			$path_candidates[$tab_root['path']] = $tab_root['path'];
		}

		// Retrieve a list of menu names, ordered by preference.
		$menu_names = menu_get_active_menu_names();
		// Put the selected menu at the front of the list.
		array_unshift($menu_names, $selected_menu);

		$query = db_select('menu_links', 'ml', array('fetch' => PDO::FETCH_ASSOC));
		$query->leftJoin('menu_router', 'm', 'm.path = ml.router_path');
		$query->fields('ml');
		// Weight must be taken from {menu_links}, not {menu_router}.
		$query->addField('ml', 'weight', 'link_weight');
		$query->fields('m');
		$query->condition('ml.link_path', $path_candidates, 'IN');

		// Sort candidates by link path and menu name.
		$candidates = array();
		foreach ($query->execute() as $candidate) {
			$candidate['weight'] = $candidate['link_weight'];
			$candidates[$candidate['link_path']][$candidate['menu_name']] = $candidate;
			// Add any menus not already in the menu name search list.
			if (!in_array($candidate['menu_name'], $menu_names)) {
				$menu_names[] = $candidate['menu_name'];
			}
		}

		// Store the most specific link for each menu. Also save the most specific
		// link of the most preferred menu in $preferred_link.
		foreach ($path_candidates as $link_path) {
			if (isset($candidates[$link_path])) {
				foreach ($menu_names as $menu_name) {
					if (empty($preferred_links[$path][$menu_name]) && isset($candidates[$link_path][$menu_name])) {
						$candidate_item = $candidates[$link_path][$menu_name];
						$map = explode('/', $path);
						_menu_translate($candidate_item, $map);
						if ($candidate_item['access']) {
							$preferred_links[$path][$menu_name] = $candidate_item;
							if (empty($preferred_links[$path][MENU_PREFERRED_LINK])) {
								// Store the most specific link.
								$preferred_links[$path][MENU_PREFERRED_LINK] = $candidate_item;
							}
						}
					}
				}
			}
		}
	}

	return isset($preferred_links[$path][$selected_menu]) ? $preferred_links[$path][$selected_menu] : FALSE;
}

/**
 * Gets the active trail (path to root menu root) of the current page.
 *
 * If a trail is supplied to menu_set_active_trail(), that value is returned. If
 * a trail is not supplied to menu_set_active_trail(), the path to the current
 * page is calculated and returned. The calculated trail is also saved as a
 * static value for use by subsequent calls to menu_get_active_trail().
 *
 * @return
 *   Path to menu root of the current page, as an array of menu link items,
 *   starting with the site's home page. Each link item is an associative array
 *   with the following components:
 *   - title: Title of the item.
 *   - href: Drupal path of the item.
 *   - localized_options: Options for passing into the l() function.
 *   - type: A menu type constant, such as MENU_DEFAULT_LOCAL_TASK, or 0 to
 *     indicate it's not really in the menu (used for the home page item).
 */
function menu_get_active_trail() {
	return menu_set_active_trail();
}

/**
 * Get the breadcrumb for the current page, as determined by the active trail.
 *
 * @see menu_set_active_trail()
 */
function menu_get_active_breadcrumb() {
	$breadcrumb = array();

	// No breadcrumb for the front page.
	if (drupal_is_front_page()) {
		return $breadcrumb;
	}

	$item = menu_get_item();
	if (!empty($item['access'])) {
		$active_trail = menu_get_active_trail();

		// Allow modules to alter the breadcrumb, if possible, as that is much
		// faster than rebuilding an entirely new active trail.
		drupal_alter('menu_breadcrumb', $active_trail, $item);

		// Don't show a link to the current page in the breadcrumb trail.
		$end = end($active_trail);
		if ($item['href'] == $end['href']) {
			array_pop($active_trail);
		}

		// Remove the tab root (parent) if the current path links to its parent.
		// Normally, the tab root link is included in the breadcrumb, as soon as we
		// are on a local task or any other child link. However, if we are on a
		// default local task (e.g., node/%/view), then we do not want the tab root
		// link (e.g., node/%) to appear, as it would be identical to the current
		// page. Since this behavior also needs to work recursively (i.e., on
		// default local tasks of default local tasks), and since the last non-task
		// link in the trail is used as page title (see menu_get_active_title()),
		// this condition cannot be cleanly integrated into menu_get_active_trail().
		// menu_get_active_trail() already skips all links that link to their parent
		// (commonly MENU_DEFAULT_LOCAL_TASK). In order to also hide the parent link
		// itself, we always remove the last link in the trail, if the current
		// router item links to its parent.
		if (($item['type'] & MENU_LINKS_TO_PARENT) == MENU_LINKS_TO_PARENT) {
			array_pop($active_trail);
		}

		foreach ($active_trail as $parent) {
			$breadcrumb[] = l($parent['title'], $parent['href'], $parent['localized_options']);
		}
	}
	return $breadcrumb;
}

/**
 * Get the title of the current page, as determined by the active trail.
 */
function menu_get_active_title() {
	$active_trail = menu_get_active_trail();

	foreach (array_reverse($active_trail) as $item) {
		if (!(bool) ($item['type'] & MENU_IS_LOCAL_TASK)) {
			return $item['title'];
		}
	}
}

/**
 * Get a menu link by its mlid, access checked and link translated for rendering.
 *
 * This function should never be called from within node_load() or any other
 * function used as a menu object load function since an infinite recursion may
 * occur.
 *
 * @param $mlid
 *   The mlid of the menu item.
 *
 * @return
 *   A menu link, with $item['access'] filled and link translated for
 *   rendering.
 */
function menu_link_load($mlid) {
	if (is_numeric($mlid)) {
		$query = db_select('menu_links', 'ml');
		$query->leftJoin('menu_router', 'm', 'm.path = ml.router_path');
		$query->fields('ml');
		// Weight should be taken from {menu_links}, not {menu_router}.
		$query->addField('ml', 'weight', 'link_weight');
		$query->fields('m');
		$query->condition('ml.mlid', $mlid);
		if ($item = $query->execute()->fetchAssoc()) {
			$item['weight'] = $item['link_weight'];
			_menu_link_translate($item);
			return $item;
		}
	}
	return FALSE;
}

/**
 * Clears the cached cached data for a single named menu.
 */
function menu_cache_clear($menu_name = 'navigation') {
	$cache_cleared = &drupal_static(__FUNCTION__, array());

	if (empty($cache_cleared[$menu_name])) {
		cache_clear_all('links:' . $menu_name . ':', 'cache_menu', TRUE);
		$cache_cleared[$menu_name] = 1;
	}
	elseif ($cache_cleared[$menu_name] == 1) {
		drupal_register_shutdown_function('cache_clear_all', 'links:' . $menu_name . ':', 'cache_menu', TRUE);
		$cache_cleared[$menu_name] = 2;
	}

	// Also clear the menu system static caches.
	menu_reset_static_cache();
}

/**
 * Clears all cached menu data. This should be called any time broad changes
 * might have been made to the router items or menu links.
 */
function menu_cache_clear_all() {
	cache_clear_all('*', 'cache_menu', TRUE);
	menu_reset_static_cache();
}

/**
 * Resets the menu system static cache.
 */
function menu_reset_static_cache() {
	drupal_static_reset('_menu_build_tree');
	drupal_static_reset('menu_tree');
	drupal_static_reset('menu_tree_all_data');
	drupal_static_reset('menu_tree_page_data');
	drupal_static_reset('menu_load_all');
	drupal_static_reset('menu_link_get_preferred');
}

/**
 * (Re)populate the database tables used by various menu functions.
 *
 * This function will clear and populate the {menu_router} table, add entries
 * to {menu_links} for new router items, then remove stale items from
 * {menu_links}. If called from update.php or install.php, it will also
 * schedule a call to itself on the first real page load from
 * menu_execute_active_handler(), because the maintenance page environment
 * is different and leaves stale data in the menu tables.
 *
 * @return
 *   TRUE if the menu was rebuilt, FALSE if another thread was rebuilding
 *   in parallel and the current thread just waited for completion.
 */
function menu_rebuild() {
	if (!lock_acquire('menu_rebuild')) {
		// Wait for another request that is already doing this work.
		// We choose to block here since otherwise the router item may not
		// be available in menu_execute_active_handler() resulting in a 404.
		lock_wait('menu_rebuild');
		return FALSE;
	}

	$transaction = db_transaction();

	try {
		list($menu, $masks) = menu_router_build();
		_menu_router_save($menu, $masks);
		_menu_navigation_links_rebuild($menu);
		// Clear the menu, page and block caches.
		menu_cache_clear_all();
		_menu_clear_page_cache();

		if (defined('MAINTENANCE_MODE')) {
			variable_set('menu_rebuild_needed', TRUE);
		}
		else {
			variable_del('menu_rebuild_needed');
		}
	}
	catch (Exception $e) {
		$transaction->rollback();
		watchdog_exception('menu', $e);
	}

	lock_release('menu_rebuild');
	return TRUE;
}

/**
 * Collect and alter the menu definitions.
 */
function menu_router_build() {
	// We need to manually call each module so that we can know which module
	// a given item came from.
	$callbacks = array();
	foreach (module_implements('menu') as $module) {
		$router_items = call_user_func($module . '_menu');
		if (isset($router_items) && is_array($router_items)) {
			foreach (array_keys($router_items) as $path) {
				$router_items[$path]['module'] = $module;
			}
			$callbacks = array_merge($callbacks, $router_items);
		}
	}
	// Alter the menu as defined in modules, keys are like user/%user.
	drupal_alter('menu', $callbacks);
	list($menu, $masks) = _menu_router_build($callbacks);
	_menu_router_cache($menu);

	return array($menu, $masks);
}

/**
 * Helper function to store the menu router if we have it in memory.
 */
function _menu_router_cache($new_menu = NULL) {
	$menu = &drupal_static(__FUNCTION__);

	if (isset($new_menu)) {
		$menu = $new_menu;
	}
	return $menu;
}

/**
 * Get the menu router.
 */
function menu_get_router() {
	// Check first if we have it in memory already.
	$menu = _menu_router_cache();
	if (empty($menu)) {
		list($menu, $masks) = menu_router_build();
	}
	return $menu;
}

/**
 * Builds a link from a router item.
 */
function _menu_link_build($item) {
	// Suggested items are disabled by default.
	if ($item['type'] == MENU_SUGGESTED_ITEM) {
		$item['hidden'] = 1;
	}
	// Hide all items that are not visible in the tree.
	elseif (!($item['type'] & MENU_VISIBLE_IN_TREE)) {
		$item['hidden'] = -1;
	}
	// Note, we set this as 'system', so that we can be sure to distinguish all
	// the menu links generated automatically from entries in {menu_router}.
	$item['module'] = 'system';
	$item += array(
			'menu_name' => 'navigation',
			'link_title' => $item['title'],
			'link_path' => $item['path'],
			'hidden' => 0,
			'options' => empty($item['description']) ? array() : array('attributes' => array('title' => $item['description'])),
	);
	return $item;
}

/**
 * Helper function to build menu links for the items in the menu router.
 */
function _menu_navigation_links_rebuild($menu) {
	// Add normal and suggested items as links.
	$menu_links = array();
	foreach ($menu as $path => $item) {
		if ($item['_visible']) {
			$menu_links[$path] = $item;
			$sort[$path] = $item['_number_parts'];
		}
	}
	if ($menu_links) {
		// Keep an array of processed menu links, to allow menu_link_save() to
		// check this for parents instead of querying the database.
		$parent_candidates = array();
		// Make sure no child comes before its parent.
		array_multisort($sort, SORT_NUMERIC, $menu_links);

		foreach ($menu_links as $key => $item) {
			$existing_item = db_select('menu_links')
			->fields('menu_links')
			->condition('link_path', $item['path'])
			->condition('module', 'system')
			->execute()->fetchAssoc();
			if ($existing_item) {
				$item['mlid'] = $existing_item['mlid'];
				// A change in hook_menu may move the link to a different menu
				if (empty($item['menu_name']) || ($item['menu_name'] == $existing_item['menu_name'])) {
					$item['menu_name'] = $existing_item['menu_name'];
					$item['plid'] = $existing_item['plid'];
				}
				else {
					// It moved to a new menu. Let menu_link_save() try to find a new
					// parent based on the path.
					unset($item['plid']);
				}
				$item['has_children'] = $existing_item['has_children'];
				$item['updated'] = $existing_item['updated'];
			}
			if ($existing_item && $existing_item['customized']) {
				$parent_candidates[$existing_item['mlid']] = $existing_item;
			}
			else {
				$item = _menu_link_build($item);
				menu_link_save($item, $existing_item, $parent_candidates);
				$parent_candidates[$item['mlid']] = $item;
				unset($menu_links[$key]);
			}
		}
	}
	$paths = array_keys($menu);
	// Updated and customized items whose router paths are gone need new ones.
	$result = db_select('menu_links', NULL, array('fetch' => PDO::FETCH_ASSOC))
	->fields('menu_links', array(
			'link_path',
			'mlid',
			'router_path',
			'updated',
	))
	->condition(db_or()
			->condition('updated', 1)
			->condition(db_and()
					->condition('router_path', $paths, 'NOT IN')
					->condition('external', 0)
					->condition('customized', 1)
			)
	)
	->execute();
	foreach ($result as $item) {
		$router_path = _menu_find_router_path($item['link_path']);
		if (!empty($router_path) && ($router_path != $item['router_path'] || $item['updated'])) {
			// If the router path and the link path matches, it's surely a working
			// item, so we clear the updated flag.
			$updated = $item['updated'] && $router_path != $item['link_path'];
			db_update('menu_links')
			->fields(array(
					'router_path' => $router_path,
					'updated' => (int) $updated,
			))
			->condition('mlid', $item['mlid'])
			->execute();
		}
	}
	// Find any item whose router path does not exist any more.
	$result = db_select('menu_links')
	->fields('menu_links')
	->condition('router_path', $paths, 'NOT IN')
	->condition('external', 0)
	->condition('updated', 0)
	->condition('customized', 0)
	->orderBy('depth', 'DESC')
	->execute();
	// Remove all such items. Starting from those with the greatest depth will
	// minimize the amount of re-parenting done by menu_link_delete().
	foreach ($result as $item) {
		_menu_delete_item($item, TRUE);
	}
}

/**
 * Clone an array of menu links.
 *
 * @param $links
 *   An array of menu links to clone.
 * @param $menu_name
 *   (optional) The name of a menu that the links will be cloned for. If not
 *   set, the cloned links will be in the same menu as the original set of
 *   links that were passed in.
 *
 * @return
 *   An array of menu links with the same properties as the passed-in array,
 *   but with the link identifiers removed so that a new link will be created
 *   when any of them is passed in to menu_link_save().
 *
 * @see menu_link_save()
 */
function menu_links_clone($links, $menu_name = NULL) {
	foreach ($links as &$link) {
		unset($link['mlid']);
		unset($link['plid']);
		if (isset($menu_name)) {
			$link['menu_name'] = $menu_name;
		}
	}
	return $links;
}

/**
 * Returns an array containing all links for a menu.
 *
 * @param $menu_name
 *   The name of the menu whose links should be returned.
 *
 * @return
 *   An array of menu links.
 */
function menu_load_links($menu_name) {
	$links = db_select('menu_links', 'ml', array('fetch' => PDO::FETCH_ASSOC))
	->fields('ml')
	->condition('ml.menu_name', $menu_name)
	// Order by weight so as to be helpful for menus that are only one level
	// deep.
	->orderBy('weight')
	->execute()
	->fetchAll();

	foreach ($links as &$link) {
		$link['options'] = unserialize($link['options']);
	}
	return $links;
}

/**
 * Deletes all links for a menu.
 *
 * @param $menu_name
 *   The name of the menu whose links will be deleted.
 */
function menu_delete_links($menu_name) {
	$links = menu_load_links($menu_name);
	foreach ($links as $link) {
		// To speed up the deletion process, we reset some link properties that
		// would trigger re-parenting logic in _menu_delete_item() and
		// _menu_update_parental_status().
		$link['has_children'] = FALSE;
		$link['plid'] = 0;
		_menu_delete_item($link);
	}
}

/**
 * Delete one or several menu links.
 *
 * @param $mlid
 *   A valid menu link mlid or NULL. If NULL, $path is used.
 * @param $path
 *   The path to the menu items to be deleted. $mlid must be NULL.
 */
function menu_link_delete($mlid, $path = NULL) {
	if (isset($mlid)) {
		_menu_delete_item(db_query("SELECT * FROM {menu_links} WHERE mlid = :mlid", array(':mlid' => $mlid))->fetchAssoc());
	}
	else {
		$result = db_query("SELECT * FROM {menu_links} WHERE link_path = :link_path", array(':link_path' => $path));
		foreach ($result as $link) {
			_menu_delete_item($link);
		}
	}
}

/**
 * Helper function for menu_link_delete; deletes a single menu link.
 *
 * @param $item
 *   Item to be deleted.
 * @param $force
 *   Forces deletion. Internal use only, setting to TRUE is discouraged.
 */
function _menu_delete_item($item, $force = FALSE) {
	$item = is_object($item) ? get_object_vars($item) : $item;
	if ($item && ($item['module'] != 'system' || $item['updated'] || $force)) {
		// Children get re-attached to the item's parent.
		if ($item['has_children']) {
			$result = db_query("SELECT mlid FROM {menu_links} WHERE plid = :plid", array(':plid' => $item['mlid']));
			foreach ($result as $m) {
				$child = menu_link_load($m->mlid);
				$child['plid'] = $item['plid'];
				menu_link_save($child);
			}
		}

		// Notify modules we are deleting the item.
		module_invoke_all('menu_link_delete', $item);

		db_delete('menu_links')->condition('mlid', $item['mlid'])->execute();

		// Update the has_children status of the parent.
		_menu_update_parental_status($item);
		menu_cache_clear($item['menu_name']);
		_menu_clear_page_cache();
	}
}

/**
 * Saves a menu link.
 *
 * After calling this function, rebuild the menu cache using
 * menu_cache_clear_all().
 *
 * @param $item
 *   An associative array representing a menu link item, with elements:
 *   - link_path: (required) The path of the menu item, which should be
 *     normalized first by calling drupal_get_normal_path() on it.
 *   - link_title: (required) Title to appear in menu for the link.
 *   - menu_name: (optional) The machine name of the menu for the link.
 *     Defaults to 'navigation'.
 *   - weight: (optional) Integer to determine position in menu. Default is 0.
 *   - expanded: (optional) Boolean that determines if the item is expanded.
 *   - options: (optional) An array of options, see l() for more.
 *   - mlid: (optional) Menu link identifier, the primary integer key for each
 *     menu link. Can be set to an existing value, or to 0 or NULL
 *     to insert a new link.
 *   - plid: (optional) The mlid of the parent.
 *   - router_path: (optional) The path of the relevant router item.
 * @param $existing_item
 *   Optional, the current record from the {menu_links} table as an array.
 * @param $parent_candidates
 *   Optional array of menu links keyed by mlid. Used by
 *   _menu_navigation_links_rebuild() only.
 *
 * @return
 *   The mlid of the saved menu link, or FALSE if the menu link could not be
 *   saved.
 */
function menu_link_save(&$item, $existing_item = array(), $parent_candidates = array()) {
	drupal_alter('menu_link', $item);

	// This is the easiest way to handle the unique internal path '<front>',
	// since a path marked as external does not need to match a router path.
	$item['external'] = (url_is_external($item['link_path'])  || $item['link_path'] == '<front>') ? 1 : 0;
	// Load defaults.
	$item += array(
			'menu_name' => 'navigation',
			'weight' => 0,
			'link_title' => '',
			'hidden' => 0,
			'has_children' => 0,
			'expanded' => 0,
			'options' => array(),
			'module' => 'menu',
			'customized' => 0,
			'updated' => 0,
	);
	if (isset($item['mlid'])) {
		if (!$existing_item) {
			$existing_item = db_query('SELECT * FROM {menu_links} WHERE mlid = :mlid', array('mlid' => $item['mlid']))->fetchAssoc();
		}
		if ($existing_item) {
			$existing_item['options'] = unserialize($existing_item['options']);
		}
	}
	else {
		$existing_item = FALSE;
	}

	// Try to find a parent link. If found, assign it and derive its menu.
	$parent = _menu_link_find_parent($item, $parent_candidates);
	if (!empty($parent['mlid'])) {
		$item['plid'] = $parent['mlid'];
		$item['menu_name'] = $parent['menu_name'];
	}
	// If no corresponding parent link was found, move the link to the top-level.
	else {
		$item['plid'] = 0;
	}
	$menu_name = $item['menu_name'];

	if (!$existing_item) {
		$item['mlid'] = db_insert('menu_links')
		->fields(array(
				'menu_name' => $item['menu_name'],
				'plid' => $item['plid'],
				'link_path' => $item['link_path'],
				'hidden' => $item['hidden'],
				'external' => $item['external'],
				'has_children' => $item['has_children'],
				'expanded' => $item['expanded'],
				'weight' => $item['weight'],
				'module' => $item['module'],
				'link_title' => $item['link_title'],
				'options' => serialize($item['options']),
				'customized' => $item['customized'],
				'updated' => $item['updated'],
		))
		->execute();
	}

	// Directly fill parents for top-level links.
	if ($item['plid'] == 0) {
		$item['p1'] = $item['mlid'];
		for ($i = 2; $i <= MENU_MAX_DEPTH; $i++) {
			$item["p$i"] = 0;
		}
		$item['depth'] = 1;
	}
	// Otherwise, ensure that this link's depth is not beyond the maximum depth
	// and fill parents based on the parent link.
	else {
		if ($item['has_children'] && $existing_item) {
			$limit = MENU_MAX_DEPTH - menu_link_children_relative_depth($existing_item) - 1;
		}
		else {
			$limit = MENU_MAX_DEPTH - 1;
		}
		if ($parent['depth'] > $limit) {
			return FALSE;
		}
		$item['depth'] = $parent['depth'] + 1;
		_menu_link_parents_set($item, $parent);
	}
	// Need to check both plid and menu_name, since plid can be 0 in any menu.
	if ($existing_item && ($item['plid'] != $existing_item['plid'] || $menu_name != $existing_item['menu_name'])) {
		_menu_link_move_children($item, $existing_item);
	}
	// Find the router_path.
	if (empty($item['router_path'])  || !$existing_item || ($existing_item['link_path'] != $item['link_path'])) {
		if ($item['external']) {
			$item['router_path'] = '';
		}
		else {
			// Find the router path which will serve this path.
			$item['parts'] = explode('/', $item['link_path'], MENU_MAX_PARTS);
			$item['router_path'] = _menu_find_router_path($item['link_path']);
		}
	}
	// If every value in $existing_item is the same in the $item, there is no
	// reason to run the update queries or clear the caches. We use
	// array_intersect_assoc() with the $item as the first parameter because
	// $item may have additional keys left over from building a router entry.
	// The intersect removes the extra keys, allowing a meaningful comparison.
	if (!$existing_item || (array_intersect_assoc($item, $existing_item)) != $existing_item) {
		db_update('menu_links')
		->fields(array(
				'menu_name' => $item['menu_name'],
				'plid' => $item['plid'],
				'link_path' => $item['link_path'],
				'router_path' => $item['router_path'],
				'hidden' => $item['hidden'],
				'external' => $item['external'],
				'has_children' => $item['has_children'],
				'expanded' => $item['expanded'],
				'weight' => $item['weight'],
				'depth' => $item['depth'],
				'p1' => $item['p1'],
				'p2' => $item['p2'],
				'p3' => $item['p3'],
				'p4' => $item['p4'],
				'p5' => $item['p5'],
				'p6' => $item['p6'],
				'p7' => $item['p7'],
				'p8' => $item['p8'],
				'p9' => $item['p9'],
				'module' => $item['module'],
				'link_title' => $item['link_title'],
				'options' => serialize($item['options']),
				'customized' => $item['customized'],
		))
		->condition('mlid', $item['mlid'])
		->execute();
		// Check the has_children status of the parent.
		_menu_update_parental_status($item);
		menu_cache_clear($menu_name);
		if ($existing_item && $menu_name != $existing_item['menu_name']) {
			menu_cache_clear($existing_item['menu_name']);
		}
		// Notify modules we have acted on a menu item.
		$hook = 'menu_link_insert';
		if ($existing_item) {
			$hook = 'menu_link_update';
		}
		module_invoke_all($hook, $item);
		// Now clear the cache.
		_menu_clear_page_cache();
	}
	return $item['mlid'];
}

/**
 * Find a possible parent for a given menu link.
 *
 * Because the parent of a given link might not exist anymore in the database,
 * we apply a set of heuristics to determine a proper parent:
 *
 *  - use the passed parent link if specified and existing.
 *  - else, use the first existing link down the previous link hierarchy
 *  - else, for system menu links (derived from hook_menu()), reparent
 *    based on the path hierarchy.
 *
 * @param $menu_link
 *   A menu link.
 * @param $parent_candidates
 *   An array of menu links keyed by mlid.
 * @return
 *   A menu link structure of the possible parent or FALSE if no valid parent
 *   has been found.
 */
function _menu_link_find_parent($menu_link, $parent_candidates = array()) {
	$parent = FALSE;

	// This item is explicitely top-level, skip the rest of the parenting.
	if (isset($menu_link['plid']) && empty($menu_link['plid'])) {
		return $parent;
	}

	// If we have a parent link ID, try to use that.
	$candidates = array();
	if (isset($menu_link['plid'])) {
		$candidates[] = $menu_link['plid'];
	}

	// Else, if we have a link hierarchy try to find a valid parent in there.
	if (!empty($menu_link['depth']) && $menu_link['depth'] > 1) {
		for ($depth = $menu_link['depth'] - 1; $depth >= 1; $depth--) {
			$candidates[] = $menu_link['p' . $depth];
		}
	}

	foreach ($candidates as $mlid) {
		if (isset($parent_candidates[$mlid])) {
			$parent = $parent_candidates[$mlid];
		}
		else {
			$parent = db_query("SELECT * FROM {menu_links} WHERE mlid = :mlid", array(':mlid' => $mlid))->fetchAssoc();
		}
		if ($parent) {
			return $parent;
		}
	}

	// If everything else failed, try to derive the parent from the path
	// hierarchy. This only makes sense for links derived from menu router
	// items (ie. from hook_menu()).
	if ($menu_link['module'] == 'system') {
		$query = db_select('menu_links');
		$query->condition('module', 'system');
		// We always respect the link's 'menu_name'; inheritance for router items is
		// ensured in _menu_router_build().
		$query->condition('menu_name', $menu_link['menu_name']);

		// Find the parent - it must be unique.
		$parent_path = $menu_link['link_path'];
		do {
			$parent = FALSE;
			$parent_path = substr($parent_path, 0, strrpos($parent_path, '/'));
			$new_query = clone $query;
			$new_query->condition('link_path', $parent_path);
			// Only valid if we get a unique result.
			if ($new_query->countQuery()->execute()->fetchField() == 1) {
				$parent = $new_query->fields('menu_links')->execute()->fetchAssoc();
			}
		} while ($parent === FALSE && $parent_path);
	}

	return $parent;
}

/**
 * Helper function to clear the page and block caches at most twice per page load.
 */
function _menu_clear_page_cache() {
	$cache_cleared = &drupal_static(__FUNCTION__, 0);

	// Clear the page and block caches, but at most twice, including at
	//  the end of the page load when there are multiple links saved or deleted.
	if ($cache_cleared == 0) {
		cache_clear_all();
		// Keep track of which menus have expanded items.
		_menu_set_expanded_menus();
		$cache_cleared = 1;
	}
	elseif ($cache_cleared == 1) {
		drupal_register_shutdown_function('cache_clear_all');
		// Keep track of which menus have expanded items.
		drupal_register_shutdown_function('_menu_set_expanded_menus');
		$cache_cleared = 2;
	}
}

/**
 * Helper function to update a list of menus with expanded items
 */
function _menu_set_expanded_menus() {
	$names = db_query("SELECT menu_name FROM {menu_links} WHERE expanded <> 0 GROUP BY menu_name")->fetchCol();
	variable_set('menu_expanded', $names);
}

/**
 * Find the router path which will serve this path.
 *
 * @param $link_path
 *  The path for we are looking up its router path.
 *
 * @return
 *  A path from $menu keys or empty if $link_path points to a nonexisting
 *  place.
 */
function _menu_find_router_path($link_path) {
	// $menu will only have data during a menu rebuild.
	$menu = _menu_router_cache();

	$router_path = $link_path;
	$parts = explode('/', $link_path, MENU_MAX_PARTS);
	$ancestors = menu_get_ancestors($parts);

	if (empty($menu)) {
		// Not during a menu rebuild, so look up in the database.
		$router_path = (string) db_select('menu_router')
		->fields('menu_router', array('path'))
		->condition('path', $ancestors, 'IN')
		->orderBy('fit', 'DESC')
		->range(0, 1)
		->execute()->fetchField();
	}
	elseif (!isset($menu[$router_path])) {
		// Add an empty router path as a fallback.
		$ancestors[] = '';
		foreach ($ancestors as $key => $router_path) {
			if (isset($menu[$router_path])) {
				// Exit the loop leaving $router_path as the first match.
				break;
			}
		}
		// If we did not find the path, $router_path will be the empty string
		// at the end of $ancestors.
	}
	return $router_path;
}

/**
 * Insert, update or delete an uncustomized menu link related to a module.
 *
 * @param $module
 *   The name of the module.
 * @param $op
 *   Operation to perform: insert, update or delete.
 * @param $link_path
 *   The path this link points to.
 * @param $link_title
 *   Title of the link to insert or new title to update the link to.
 *   Unused for delete.
 *
 * @return
 *   The insert op returns the mlid of the new item. Others op return NULL.
 */
function menu_link_maintain($module, $op, $link_path, $link_title) {
	switch ($op) {
		case 'insert':
			$menu_link = array(
			'link_title' => $link_title,
			'link_path' => $link_path,
			'module' => $module,
			);
			return menu_link_save($menu_link);
			break;
		case 'update':
			$result = db_query("SELECT * FROM {menu_links} WHERE link_path = :link_path AND module = :module AND customized = 0", array(':link_path' => $link_path, ':module' => $module))->fetchAll(PDO::FETCH_ASSOC);
			foreach ($result as $link) {
				$link['link_title'] = $link_title;
				$link['options'] = unserialize($link['options']);
				menu_link_save($link);
			}
			break;
		case 'delete':
			menu_link_delete(NULL, $link_path);
			break;
	}
}

/**
 * Find the depth of an item's children relative to its depth.
 *
 * For example, if the item has a depth of 2, and the maximum of any child in
 * the menu link tree is 5, the relative depth is 3.
 *
 * @param $item
 *   An array representing a menu link item.
 *
 * @return
 *   The relative depth, or zero.
 *
 */
function menu_link_children_relative_depth($item) {
	$query = db_select('menu_links');
	$query->addField('menu_links', 'depth');
	$query->condition('menu_name', $item['menu_name']);
	$query->orderBy('depth', 'DESC');
	$query->range(0, 1);

	$i = 1;
	$p = 'p1';
	while ($i <= MENU_MAX_DEPTH && $item[$p]) {
		$query->condition($p, $item[$p]);
		$p = 'p' . ++$i;
	}

	$max_depth = $query->execute()->fetchField();

	return ($max_depth > $item['depth']) ? $max_depth - $item['depth'] : 0;
}

/**
 * Update the children of a menu link that's being moved.
 *
 * The menu name, parents (p1 - p6), and depth are updated for all children of
 * the link, and the has_children status of the previous parent is updated.
 */
function _menu_link_move_children($item, $existing_item) {
	$query = db_update('menu_links');

	$query->fields(array('menu_name' => $item['menu_name']));

	$p = 'p1';
	$expressions = array();
	for ($i = 1; $i <= $item['depth']; $p = 'p' . ++$i) {
		$expressions[] = array($p, ":p_$i", array(":p_$i" => $item[$p]));
	}
	$j = $existing_item['depth'] + 1;
	while ($i <= MENU_MAX_DEPTH && $j <= MENU_MAX_DEPTH) {
		$expressions[] = array('p' . $i++, 'p' . $j++, array());
	}
	while ($i <= MENU_MAX_DEPTH) {
		$expressions[] = array('p' . $i++, 0, array());
	}

	$shift = $item['depth'] - $existing_item['depth'];
	if ($shift > 0) {
		// The order of expressions must be reversed so the new values don't
		// overwrite the old ones before they can be used because "Single-table
		// UPDATE assignments are generally evaluated from left to right"
		// see: http://dev.mysql.com/doc/refman/5.0/en/update.html
		$expressions = array_reverse($expressions);
	}
	foreach ($expressions as $expression) {
		$query->expression($expression[0], $expression[1], $expression[2]);
	}

	$query->expression('depth', 'depth + :depth', array(':depth' => $shift));
	$query->condition('menu_name', $existing_item['menu_name']);
	$p = 'p1';
	for ($i = 1; $i <= MENU_MAX_DEPTH && $existing_item[$p]; $p = 'p' . ++$i) {
		$query->condition($p, $existing_item[$p]);
	}

	$query->execute();

	// Check the has_children status of the parent, while excluding this item.
	_menu_update_parental_status($existing_item, TRUE);
}

/**
 * Check and update the has_children status for the parent of a link.
 */
function _menu_update_parental_status($item, $exclude = FALSE) {
	// If plid == 0, there is nothing to update.
	if ($item['plid']) {
		// Check if at least one visible child exists in the table.
		$query = db_select('menu_links');
		$query->addField('menu_links', 'mlid');
		$query->condition('menu_name', $item['menu_name']);
		$query->condition('hidden', 0);
		$query->condition('plid', $item['plid']);
		$query->range(0, 1);
		if ($exclude) {
			$query->condition('mlid', $item['mlid'], '<>');
		}
		$parent_has_children = ((bool) $query->execute()->fetchField()) ? 1 : 0;
		db_update('menu_links')
		->fields(array('has_children' => $parent_has_children))
		->condition('mlid', $item['plid'])
		->execute();
	}
}

/**
 * Helper function that sets the p1..p9 values for a menu link being saved.
 */
function _menu_link_parents_set(&$item, $parent) {
	$i = 1;
	while ($i < $item['depth']) {
		$p = 'p' . $i++;
		$item[$p] = $parent[$p];
	}
	$p = 'p' . $i++;
	// The parent (p1 - p9) corresponding to the depth always equals the mlid.
	$item[$p] = $item['mlid'];
	while ($i <= MENU_MAX_DEPTH) {
		$p = 'p' . $i++;
		$item[$p] = 0;
	}
}

/**
 * Helper function to build the router table based on the data from hook_menu.
 */
function _menu_router_build($callbacks) {
	// First pass: separate callbacks from paths, making paths ready for
	// matching. Calculate fitness, and fill some default values.
	$menu = array();
	$masks = array();
	foreach ($callbacks as $path => $item) {
		$load_functions = array();
		$to_arg_functions = array();
		$fit = 0;
		$move = FALSE;

		$parts = explode('/', $path, MENU_MAX_PARTS);
		$number_parts = count($parts);
		// We store the highest index of parts here to save some work in the fit
		// calculation loop.
		$slashes = $number_parts - 1;
		// Extract load and to_arg functions.
		foreach ($parts as $k => $part) {
			$match = FALSE;
			// Look for wildcards in the form allowed to be used in PHP functions,
			// because we are using these to construct the load function names.
			if (preg_match('/^%(|' . DRUPAL_PHP_FUNCTION_PATTERN . ')$/', $part, $matches)) {
				if (empty($matches[1])) {
					$match = TRUE;
					$load_functions[$k] = NULL;
				}
				else {
					if (function_exists($matches[1] . '_to_arg')) {
						$to_arg_functions[$k] = $matches[1] . '_to_arg';
						$load_functions[$k] = NULL;
						$match = TRUE;
					}
					if (function_exists($matches[1] . '_load')) {
						$function = $matches[1] . '_load';
						// Create an array of arguments that will be passed to the _load
						// function when this menu path is checked, if 'load arguments'
						// exists.
						$load_functions[$k] = isset($item['load arguments']) ? array($function => $item['load arguments']) : $function;
						$match = TRUE;
					}
				}
			}
			if ($match) {
				$parts[$k] = '%';
			}
			else {
				$fit |=  1 << ($slashes - $k);
			}
		}
		if ($fit) {
			$move = TRUE;
		}
		else {
			// If there is no %, it fits maximally.
			$fit = (1 << $number_parts) - 1;
		}
		$masks[$fit] = 1;
		$item['_load_functions'] = $load_functions;
		$item['to_arg_functions'] = empty($to_arg_functions) ? '' : serialize($to_arg_functions);
		$item += array(
				'title' => '',
				'weight' => 0,
				'type' => MENU_NORMAL_ITEM,
				'module' => '',
				'_number_parts' => $number_parts,
				'_parts' => $parts,
				'_fit' => $fit,
		);
		$item += array(
				'_visible' => (bool) ($item['type'] & MENU_VISIBLE_IN_BREADCRUMB),
				'_tab' => (bool) ($item['type'] & MENU_IS_LOCAL_TASK),
		);
		if ($move) {
			$new_path = implode('/', $item['_parts']);
			$menu[$new_path] = $item;
			$sort[$new_path] = $number_parts;
		}
		else {
			$menu[$path] = $item;
			$sort[$path] = $number_parts;
		}
	}
	array_multisort($sort, SORT_NUMERIC, $menu);
	// Apply inheritance rules.
	foreach ($menu as $path => $v) {
		$item = &$menu[$path];
		if (!$item['_tab']) {
			// Non-tab items.
			$item['tab_parent'] = '';
			$item['tab_root'] = $path;
		}
		// If not specified, assign the default tab type for local tasks.
		elseif (!isset($item['context'])) {
			$item['context'] = MENU_CONTEXT_PAGE;
		}
		for ($i = $item['_number_parts'] - 1; $i; $i--) {
			$parent_path = implode('/', array_slice($item['_parts'], 0, $i));
			if (isset($menu[$parent_path])) {

				$parent = &$menu[$parent_path];

				// If we have no menu name, try to inherit it from parent items.
				if (!isset($item['menu_name'])) {
					// If the parent item of this item does not define a menu name (and no
					// previous iteration assigned one already), try to find the menu name
					// of the parent item in the currently stored menu links.
					if (!isset($parent['menu_name'])) {
						$menu_name = db_query("SELECT menu_name FROM {menu_links} WHERE router_path = :router_path AND module = 'system'", array(':router_path' => $parent_path))->fetchField();
						if ($menu_name) {
							$parent['menu_name'] = $menu_name;
						}
					}
					// If the parent item defines a menu name, inherit it.
					if (!empty($parent['menu_name'])) {
						$item['menu_name'] = $parent['menu_name'];
					}
				}
				if (!isset($item['tab_parent'])) {
					// Parent stores the parent of the path.
					$item['tab_parent'] = $parent_path;
				}
				if (!isset($item['tab_root']) && !$parent['_tab']) {
					$item['tab_root'] = $parent_path;
				}
				// If an access callback is not found for a default local task we use
				// the callback from the parent, since we expect them to be identical.
				// In all other cases, the access parameters must be specified.
				if (($item['type'] == MENU_DEFAULT_LOCAL_TASK) && !isset($item['access callback']) && isset($parent['access callback'])) {
					$item['access callback'] = $parent['access callback'];
					if (!isset($item['access arguments']) && isset($parent['access arguments'])) {
						$item['access arguments'] = $parent['access arguments'];
					}
				}
				// Same for page callbacks.
				if (!isset($item['page callback']) && isset($parent['page callback'])) {
					$item['page callback'] = $parent['page callback'];
					if (!isset($item['page arguments']) && isset($parent['page arguments'])) {
						$item['page arguments'] = $parent['page arguments'];
					}
					if (!isset($item['file path']) && isset($parent['file path'])) {
						$item['file path'] = $parent['file path'];
					}
					if (!isset($item['file']) && isset($parent['file'])) {
						$item['file'] = $parent['file'];
						if (empty($item['file path']) && isset($item['module']) && isset($parent['module']) && $item['module'] != $parent['module']) {
							$item['file path'] = drupal_get_path('module', $parent['module']);
						}
					}
				}
				// Same for delivery callbacks.
				if (!isset($item['delivery callback']) && isset($parent['delivery callback'])) {
					$item['delivery callback'] = $parent['delivery callback'];
				}
				// Same for theme callbacks.
				if (!isset($item['theme callback']) && isset($parent['theme callback'])) {
					$item['theme callback'] = $parent['theme callback'];
					if (!isset($item['theme arguments']) && isset($parent['theme arguments'])) {
						$item['theme arguments'] = $parent['theme arguments'];
					}
				}
				// Same for load arguments: if a loader doesn't have any explict
				// arguments, try to find arguments in the parent.
				if (!isset($item['load arguments'])) {
					foreach ($item['_load_functions'] as $k => $function) {
						// This loader doesn't have any explict arguments...
						if (!is_array($function)) {
							// ... check the parent for a loader at the same position
							// using the same function name and defining arguments...
							if (isset($parent['_load_functions'][$k]) && is_array($parent['_load_functions'][$k]) && key($parent['_load_functions'][$k]) === $function) {
								// ... and inherit the arguments on the child.
								$item['_load_functions'][$k] = $parent['_load_functions'][$k];
							}
						}
					}
				}
			}
		}
		if (!isset($item['access callback']) && isset($item['access arguments'])) {
			// Default callback.
			$item['access callback'] = 'user_access';
		}
		if (!isset($item['access callback']) || empty($item['page callback'])) {
			$item['access callback'] = 0;
		}
		if (is_bool($item['access callback'])) {
			$item['access callback'] = intval($item['access callback']);
		}

		$item['load_functions'] = empty($item['_load_functions']) ? '' : serialize($item['_load_functions']);
		$item += array(
				'access arguments' => array(),
				'access callback' => '',
				'page arguments' => array(),
				'page callback' => '',
				'delivery callback' => '',
				'title arguments' => array(),
				'title callback' => 't',
				'theme arguments' => array(),
				'theme callback' => '',
				'description' => '',
				'position' => '',
				'context' => 0,
				'tab_parent' => '',
				'tab_root' => $path,
				'path' => $path,
				'file' => '',
				'file path' => '',
				'include file' => '',
		);

		// Calculate out the file to be included for each callback, if any.
		if ($item['file']) {
			$file_path = $item['file path'] ? $item['file path'] : drupal_get_path('module', $item['module']);
			$item['include file'] = $file_path . '/' . $item['file'];
		}
	}

	// Sort the masks so they are in order of descending fit.
	$masks = array_keys($masks);
	rsort($masks);

	return array($menu, $masks);
}

/**
 * Helper function to save data from menu_router_build() to the router table.
 */
function _menu_router_save($menu, $masks) {
	// Delete the existing router since we have some data to replace it.
	db_truncate('menu_router')->execute();

	// Prepare insert object.
	$insert = db_insert('menu_router')
	->fields(array(
			'path',
			'load_functions',
			'to_arg_functions',
			'access_callback',
			'access_arguments',
			'page_callback',
			'page_arguments',
			'delivery_callback',
			'fit',
			'number_parts',
			'context',
			'tab_parent',
			'tab_root',
			'title',
			'title_callback',
			'title_arguments',
			'theme_callback',
			'theme_arguments',
			'type',
			'description',
			'position',
			'weight',
			'include_file',
	));

	$num_records = 0;

	foreach ($menu as $path => $item) {
		// Fill in insert object values.
		$insert->values(array(
				'path' => $item['path'],
				'load_functions' => $item['load_functions'],
				'to_arg_functions' => $item['to_arg_functions'],
				'access_callback' => $item['access callback'],
				'access_arguments' => serialize($item['access arguments']),
				'page_callback' => $item['page callback'],
				'page_arguments' => serialize($item['page arguments']),
				'delivery_callback' => $item['delivery callback'],
				'fit' => $item['_fit'],
				'number_parts' => $item['_number_parts'],
				'context' => $item['context'],
				'tab_parent' => $item['tab_parent'],
				'tab_root' => $item['tab_root'],
				'title' => $item['title'],
				'title_callback' => $item['title callback'],
				'title_arguments' => ($item['title arguments'] ? serialize($item['title arguments']) : ''),
				'theme_callback' => $item['theme callback'],
				'theme_arguments' => serialize($item['theme arguments']),
				'type' => $item['type'],
				'description' => $item['description'],
				'position' => $item['position'],
				'weight' => $item['weight'],
				'include_file' => $item['include file'],
		));

		// Execute in batches to avoid the memory overhead of all of those records
		// in the query object.
		if (++$num_records == 20) {
			$insert->execute();
			$num_records = 0;
		}
	}
	// Insert any remaining records.
	$insert->execute();
	// Store the masks.
	variable_set('menu_masks', $masks);

	return $menu;
}

/**
 * Checks whether the site is in maintenance mode.
 *
 * This function will log the current user out and redirect to front page
 * if the current user has no 'access site in maintenance mode' permission.
 *
 * @param $check_only
 *   If this is set to TRUE, the function will perform the access checks and
 *   return the site offline status, but not log the user out or display any
 *   messages.
 *
 * @return
 *   FALSE if the site is not in maintenance mode, the user login page is
 *   displayed, or the user has the 'access site in maintenance mode'
 *   permission. TRUE for anonymous users not being on the login page when the
 *   site is in maintenance mode.
 */
function _menu_site_is_offline($check_only = FALSE) {
	// Check if site is in maintenance mode.
	if (variable_get('maintenance_mode', 0)) {
		if (user_access('access site in maintenance mode')) {
			// Ensure that the maintenance mode message is displayed only once
			// (allowing for page redirects) and specifically suppress its display on
			// the maintenance mode settings page.
			if (!$check_only && $_GET['q'] != 'admin/config/development/maintenance') {
				if (user_access('administer site configuration')) {
					drupal_set_message(t('Operating in maintenance mode. <a href="@url">Go online.</a>', array('@url' => url('admin/config/development/maintenance'))), 'status', FALSE);
				}
				else {
					drupal_set_message(t('Operating in maintenance mode.'), 'status', FALSE);
				}
			}
		}
		else {
			return TRUE;
		}
	}
	return FALSE;
}

/**
 * @} End of "defgroup menu".
 */
